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Rodríguez Rondón AV, Welling MS, van den Akker ELT, van Rossum EFC, Boon EMJ, van Haelst MM, Delhanty PJD, Visser JA. MC4R variants modulate α-MSH and setmelanotide induced cellular signaling at multiple levels. J Clin Endocrinol Metab 2024:dgae210. [PMID: 38567654 DOI: 10.1210/clinem/dgae210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/10/2024] [Indexed: 04/04/2024]
Abstract
CONTEXT Melanocortin-4 receptor (MC4R) plays an important role in body weight regulation. Pathogenic MC4R variants are the most common cause of monogenic obesity. OBJECTIVE We have identified 17 MC4R variants in adult and pediatric patients with obesity. Here, we aimed to functionally characterize these variants by analyzing four different aspects of MC4R signaling. In addition, we aimed to analyze the effect of setmelanotide, a potent MC4R agonist, on these MC4R variants. MATERIALS AND METHODS Cell surface expression and α-MSH- or setmelanotide-induced cAMP response, β-arrestin-2 recruitment, and ERK activation were measured in cells expressing either wild type (WT) or variant MC4R. RESULTS We found a large heterogeneity in the function of these variants. We identified variants with a loss of response for all studied MC4R signaling, variants with no cAMP accumulation or ERK activation but normal β-arrestin-2 recruitment, and variants with normal cAMP accumulation and ERK activation but decreased β-arrestin-2 recruitment, indicating disrupted desensitization and signaling mechanisms. Setmelanotide displayed a greater potency and similar efficacy as α-MSH, and induced significantly increased maximal cAMP responses of several variants compared to α-MSH. Despite the heterogeneity in functional response, there was no apparent difference in the obesity phenotype in our patients. DISCUSSION We show that these obesity-associated MC4R variants affect MC4R signaling differently, yet leading to a comparable clinical phenotype. Our results demonstrate the clinical importance of assessing the effect of MC4R variants on a range of molecular signaling mechanisms to determine their association with obesity, which may aid in improving personalized treatment.
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Affiliation(s)
- Alejandra V Rodríguez Rondón
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Mila S Welling
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Pediatrics, Division of Endocrinology, Erasmus MC-Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Erica L T van den Akker
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Pediatrics, Division of Endocrinology, Erasmus MC-Sophia Children's Hospital, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Elisabeth F C van Rossum
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Elles M J Boon
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Mieke M van Haelst
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Patric J D Delhanty
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Jenny A Visser
- Obesity Center CGG and expertise center genetic obesity, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
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Grootjen LN, Diene G, Molinas C, Beauloye V, Huisman TM, Visser JA, Delhanty PJD, Kerkhof GF, Tauber M, Hokken-Koelega ACS. Longitudinal changes in acylated versus unacylated ghrelin levels may be involved in the underlying mechanisms of the switch in nutritional phases in Prader-Willi syndrome. Horm Res Paediatr 2023:000534560. [PMID: 37839403 DOI: 10.1159/000534560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/30/2023] [Indexed: 10/17/2023] Open
Abstract
INTRODUCTION Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. An elevated, more unfavorable ratio between acylated and unacylated ghrelin (AG/UAG ratio) might play a role in the underlying mechanisms of this switch. We aimed to assess the evolution of the appetite regulating hormones acylated ghrelin (AG) and unacylated ghrelin (UAG) and the AG/UAG ratio and their association with the change in eating behavior in children with PWS, compared to healthy age-matched controls. METHODS Longitudinal study in 134 children with PWS and 157 healthy controls, from The Netherlands, France and Belgium. Levels of AG and UAG and the AG/UAG ratio were measured and nutritional phases as reported for PWS were scored. RESULTS The AG/UAG ratio was in the first years of life lower in PWS than in controls and started to increase from the age of 3 years, resulting in a high-normal AG/UAG ratio compared to controls. The AG levels remained stable during the different nutritional phases (p=0.114), while the UAG levels decreased from 290 pg/ml in phase 1a to 137 pg/ml in phase 2b (p<0.001). The AG/UAG ratio increased significantly from 0.81 in phase 2a to 1.24 in phase 2b (p= 0.012). CONCLUSIONS The change from failure to thrive to excessive weight gain and hyperphagia in infants and children with PWS coincides with an increase in AG/UAG ratio. The increase in AG/UAG ratio occurred during phase 2a, thus before the onset of hyperphagia.
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Kuckuck S, van der Valk ES, Scheurink AJW, van der Voorn B, Iyer AM, Visser JA, Delhanty PJD, van den Berg SAA, van Rossum EFC. Glucocorticoids, stress and eating: The mediating role of appetite-regulating hormones. Obes Rev 2023; 24:e13539. [PMID: 36480471 PMCID: PMC10077914 DOI: 10.1111/obr.13539] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/07/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2022]
Abstract
Disrupted hormonal appetite signaling plays a crucial role in obesity as it may lead to uncontrolled reward-related eating. Such disturbances can be induced not only by weight gain itself but also by glucocorticoid overexposure, for example, due to chronic stress, disease, or medication use. However, the exact pathways are just starting to be understood. Here, we present a conceptual framework of how glucocorticoid excess may impair hormonal appetite signaling and, consequently, eating control in the context of obesity. The evidence we present suggests that counteracting glucocorticoid excess can lead to improvements in appetite signaling and may therefore pose a crucial target for obesity prevention and treatment. In turn, targeting hormonal appetite signals may not only improve weight management and eating behavior but may also decrease detrimental effects of glucocorticoid excess on cardio-metabolic outcomes and mood. We conclude that gaining a better understanding of the relationship between glucocorticoid excess and circulating appetite signals will contribute greatly to improvements in personalized obesity prevention and treatment.
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Affiliation(s)
- Susanne Kuckuck
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Obesity Center CGG, Erasmus MC, Room Rg528, P.O. Box 2040, Rotterdam, 3000 CA, Netherlands
| | - Eline S van der Valk
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Obesity Center CGG, Erasmus MC, Room Rg528, P.O. Box 2040, Rotterdam, 3000 CA, Netherlands
| | - Anton J W Scheurink
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Bibian van der Voorn
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Obesity Center CGG, Erasmus MC, Room Rg528, P.O. Box 2040, Rotterdam, 3000 CA, Netherlands
| | - Anand M Iyer
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Obesity Center CGG, Erasmus MC, Room Rg528, P.O. Box 2040, Rotterdam, 3000 CA, Netherlands
| | - Jenny A Visser
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands
| | - Patric J D Delhanty
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands
| | - Sjoerd A A van den Berg
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Department of Clinical Chemistry, Erasmus MC, Rotterdam, Netherlands
| | - Elisabeth F C van Rossum
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, Rotterdam, Netherlands.,Obesity Center CGG, Erasmus MC, Room Rg528, P.O. Box 2040, Rotterdam, 3000 CA, Netherlands
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van der Valk ES, Kleinendorst L, Delhanty PJD, van der Voorn B, Visser JA, van Haelst MM, de Graaff LCG, Huisman M, White A, Ito S, Wakamatsu K, de Rijke YB, van den Akker ELT, Iyer AM, van Rossum EFC. Obesity and Hyperphagia With Increased Defective ACTH: A Novel POMC Variant. J Clin Endocrinol Metab 2022; 107:e3699-e3704. [PMID: 35737586 PMCID: PMC9797039 DOI: 10.1210/clinem/dgac342] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Patients with pro-opiomelanocortin (POMC) defects generally present with early-onset obesity, hyperphagia, hypopigmentation and adrenocorticotropin (ACTH) deficiency. Rodent models suggest that adequate cleavage of ACTH to α-melanocortin-stimulating hormone (α-MSH) and desacetyl-α-melanocortin-stimulating hormone (d-α-MSH) by prohormone convertase 2 at the KKRR region is required for regulating food intake and energy balance. METHODS We present 2 sisters with a novel POMC gene variant, leading to an ACTH defect at the prohormone convertase 2 cleavage site, and performed functional studies of this variant. RESULTS The patients had obesity, hyperphagia and hypocortisolism, with markerly raised levels of ACTH but unaffected pigmentation. Their ACTH has reduced potency to stimulate the melanocortin (MC) 2 receptor, explaining their hypocortisolism. CONCLUSION The hyperphagia and obesity support evidence that adequate cleavage of ACTH to α-MSH and d-α-MSH is also required in humans for feeding control.
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Affiliation(s)
- Eline S van der Valk
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | | | | | - Bibian van der Voorn
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Jenny A Visser
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - M M van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1100 DD Amsterdam, the Netherlands
| | - Laura C G de Graaff
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Anne White
- Divison of Diabetes, Endocrinology & Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, 470-1192, Japan
| | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, 470-1192, Japan
| | - Yolanda B de Rijke
- Department of Clinical Chemistry, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Erica L T van den Akker
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Anand M Iyer
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Elisabeth F C van Rossum
- Correspondence: Elisabeth F. C. van Rossum, MD, PhD, Obesity Center CGG (Centrum Gezond Gewicht), Erasmus MC, University Medical Center Rotterdam, the Netherlands, Rm Rg-5. P. O. Box 2400, 3000 CA Rotterdam, the Netherlands.
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Prins K, Huisman M, McLuskey A, Mies R, Karels B, Delhanty PJD, Visser JA. Ghrelin deficiency sex-dependently affects food intake, locomotor activity, and adipose and hepatic gene expression in a binge-eating mouse model. Am J Physiol Endocrinol Metab 2022; 322:E494-E507. [PMID: 35403437 DOI: 10.1152/ajpendo.00432.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Binge-eating disorder is the most prevalent eating disorder diagnosed, affecting three times more women than men. Ghrelin stimulates appetite and reward signaling, and loss of its receptor reduces binge-eating behavior in male mice. Here, we examined the influence of ghrelin itself on binge-eating behavior in both male and female mice. Five-wk-old wild-type (WT) and ghrelin-deficient (Ghrl-/-) mice were housed individually in indirect calorimetry cages for 9 wks. Binge-like eating was induced by giving mice ad libitum chow, but time-restricted access to a Western-style diet (WD; 2 h access, 3 days/wk) in the light phase (BE); control groups received ad libitum chow (CO), or ad libitum access to both diets (CW). All groups of BE mice showed binge-eating behavior, eating up to 60% of their 24-h intake during the WD access period. Subsequent dark phase chow intake was decreased in Ghrl-/- mice and remained decreased in Ghrl-/- females on nonbinge days. Also, nonbinge day locomotor activity was lower in Ghrl-/- than in WT BE females. Upon euthanasia, Ghrl-/- BE mice weighed less and had a lower lean body mass percentage than WT BE mice. In BE and CW groups, ghrelin and sex altered the expression of genes involved in lipid processing, thermogenesis, and aging in white adipose tissue and livers. We conclude that, although ghrelin deficiency does not hamper the development of binge-like eating, it sex-dependently alters food intake timing, locomotor activity, and metabolism. These results add to the growing body of evidence that ghrelin signaling is sexually dimorphic.NEW & NOTEWORTHY Ghrelin, a peptide hormone secreted from the gut, is involved in hunger and reward signaling, which are altered in binge-eating disorder. Although sex differences have been described in both binge-eating and ghrelin signaling, this interaction has not been fully elucidated. Here, we show that ghrelin deficiency affects the behavior and metabolism of mice in a binge-like eating paradigm, and that the sex of the mice impacts the magnitude and direction of these effects.
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Affiliation(s)
- Karina Prins
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Anke McLuskey
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Rosinda Mies
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Bas Karels
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Patric J D Delhanty
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Jenny A Visser
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Vlug LE, Delhanty PJD, Neelis EG, Huisman M, Visser JA, Rings EHHM, Wijnen RMH, Nagelkerke SCJ, Tabbers MM, Hulst JM, de Koning BAE. Ghrelin Levels in Children With Intestinal Failure Receiving Long-Term Parenteral Nutrition. Front Nutr 2022; 9:896328. [PMID: 35634374 PMCID: PMC9131070 DOI: 10.3389/fnut.2022.896328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/22/2022] [Indexed: 12/02/2022] Open
Abstract
Background Children with intestinal failure (IF) require parenteral nutrition (PN). Transition to oral and enteral nutrition (EN) can be difficult also due to abnormal gastrointestinal motility. The gut hormone ghrelin is increased in states of negative energy balance, functioning to preserve euglycemia, and also has appetite stimulating and prokinetic properties. We aimed to evaluate and compare ghrelin levels in children with IF, and to assess the relationship with PN-dependency. Methods In this exploratory prospective multicenter study, plasma acylated (AG) and unacylated (UAG) ghrelin levels were measured in children with short bowel syndrome (SBS) and with functional IF (pseudo-obstruction or any enteropathy) and compared with healthy control subjects. Spearman’s rho (rs) was used to assess correlations of AG and UAG with PN-dependency (%PN) and parenteral glucose intake. Results Sixty-four samples from 36 IF-patients were analyzed. Median baseline AG and UAG levels were respectively 279.2 and 101.0 pg/mL in children with SBS (n = 16), 126.4 and 84.5 pg/mL in children with functional IF (n = 20) and 82.4 and 157.3 pg/mL in healthy children (n = 39). AG levels were higher in children with SBS and functional IF than in healthy children (p = 0.002 and p = 0.023, respectively). In SBS, AG positively correlated with %PN (rs = 0.5, p = 0.005) and parenteral glucose intake (rs = 0.6, p = 0.003). These correlations were not observed in functional IF. Conclusion Children with IF had raised AG levels which could be related to starvation of the gut. The positive correlation between AG and glucose infusion rate in SBS suggests an altered glucoregulatory function.
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Affiliation(s)
- Lotte E. Vlug
- Division of Gastroenterology, Department of Pediatrics, Erasmus MC Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Patric J. D. Delhanty
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Esther G. Neelis
- Division of Gastroenterology, Department of Pediatrics, Erasmus MC Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Jenny A. Visser
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Edmond H. H. M. Rings
- Division of Gastroenterology, Department of Pediatrics, Erasmus MC Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, Netherlands
- Division of Gastroenterology, Department of Pediatrics, Willem Alexander Children’s Hospital, Leiden University Medical Center, Leiden, Netherlands
| | - René M. H. Wijnen
- Department of Pediatric Surgery, Erasmus MC Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Sjoerd C. J. Nagelkerke
- Division of Gastroenterology, Department of Pediatrics, Emma Children’s Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Merit M. Tabbers
- Division of Gastroenterology, Department of Pediatrics, Emma Children’s Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Jessie M. Hulst
- Division of Paediatric Gastroenterology, Hepatology and Nutrition, The Hospital for Sick Children, Toronto, ON, Canada
| | - Barbara A. E. de Koning
- Division of Gastroenterology, Department of Pediatrics, Erasmus MC Sophia Children’s Hospital, University Medical Center Rotterdam, Rotterdam, Netherlands
- *Correspondence: Barbara A. E. de Koning,
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van Santen SS, Wolf P, Kremenevski N, Boguszewski CL, Beiglböck H, Fiocco M, Wijnen M, Wallenius VR, van den Heuvel-Eibrink MM, van der Lely AJ, Johannsson G, Luger A, Krebs M, Buchfelder M, Delhanty PJD, Neggers SJCMM, Olsson DS. Bariatric Surgery for Hypothalamic Obesity in Craniopharyngioma Patients: A Retrospective, Matched Case-Control Study. J Clin Endocrinol Metab 2021; 106:e4734-e4745. [PMID: 34265053 PMCID: PMC8530717 DOI: 10.1210/clinem/dgab518] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Craniopharyngioma is a sellar tumor associated with high rates of pituitary deficiencies (~ 98%) and hypothalamic obesity (~ 50%). OBJECTIVE This work aims to determine the efficacy regarding long-term weight loss after bariatric surgery in obese craniopharyngioma patients with hypothalamic dysfunction. METHODS This retrospective, case-control, multicenter, international study included obese craniopharyngioma patients (N = 16; of whom 12 are women) with a history of bariatric surgery (12 Roux-en-Y gastric bypass, 4 sleeve gastrectomy; median age 21 years [range, 15-52 years], median follow-up 5.2 years [range, 2.0-11.3 years]) and age/sex/surgery/body mass index-matched obese controls (N = 155). Weight loss and obesity-related comorbidities up to 5 years after bariatric surgery were compared and changes in hormonal replacement therapy evaluated. RESULTS Mean weight loss at 5-year follow-up was 22.0% (95% CI, 16.1%-27.8%) in patients vs 29.5% (95% CI, 28.0%-30.9%) in controls (P = .02), which was less after Roux-en-Y gastric bypass (22.7% [16.9%-28.5%] vs 32.0% [30.4%-33.6%]; P = .003) but at a similar level after sleeve gastrectomy (21.7% [-1.8% to 45.2%] vs 21.8% [18.2%-25.5%]; P = .96). No major changes in endocrine replacement therapy were observed after surgery. One patient died (unknown cause). One patient had long-term absorptive problems. CONCLUSION Obese patients with craniopharyngioma had a substantial mean weight loss of 22% at 5-year follow-up after bariatric surgery, independent of type of bariatric surgery procedure. Weight loss was lower than in obese controls after Roux-en-Y gastric bypass. Bariatric surgery appears to be effective and relatively safe in the treatment of obese craniopharyngioma patients.
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Affiliation(s)
- Selveta S van Santen
- Department of Endocrinology; Erasmus Medical Center, CE Rotterdam, the Netherlands
- Princess Máxima Center for Paediatric Oncology, CS Utrecht, the Netherlands
| | - Peter Wolf
- Department of Endocrinology and Metabolism; Medical University of Vienna, Vienna, Austria
| | - Natalia Kremenevski
- Department of Neurosurgery; University Hospital Erlangen-Nuremberg, Erlangen, Germany
| | - Cesar L Boguszewski
- Department of Internal Medicine; Universidade Federal do Paraná, Curitiba, Brazil
| | - Hannes Beiglböck
- Department of Endocrinology and Metabolism; Medical University of Vienna, Vienna, Austria
| | - Marta Fiocco
- Princess Máxima Center for Paediatric Oncology, CS Utrecht, the Netherlands
- Mathematical Institute, Leiden University, CA Leiden, the Netherlands
- Department of Biomedical Data Sciences, Medical Statistics Section, Leiden University Medical Center, ZA Leiden, the Netherlands
| | - Mark Wijnen
- Department of Endocrinology; Erasmus Medical Center, CE Rotterdam, the Netherlands
| | - Ville R Wallenius
- Department of Gastrosurgical Research and Education; Sahlgrenska University Hospital, Gothenburg, Sweden
| | | | - Aart J van der Lely
- Department of Endocrinology; Erasmus Medical Center, CE Rotterdam, the Netherlands
| | - Gudmundur Johannsson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Endocrinology at Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Anton Luger
- Department of Endocrinology and Metabolism; Medical University of Vienna, Vienna, Austria
| | - Michael Krebs
- Department of Endocrinology and Metabolism; Medical University of Vienna, Vienna, Austria
| | - Michael Buchfelder
- Department of Neurosurgery; University Hospital Erlangen-Nuremberg, Erlangen, Germany
| | - Patric J D Delhanty
- Department of Endocrinology; Erasmus Medical Center, CE Rotterdam, the Netherlands
| | - Sebastian J C M M Neggers
- Department of Endocrinology; Erasmus Medical Center, CE Rotterdam, the Netherlands
- Princess Máxima Center for Paediatric Oncology, CS Utrecht, the Netherlands
- Correspondence: Sebastian J. C. M. M. Neggers, MD, Erasmus Medical Center, Department of Internal Medicine, Endocrinology, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, the Netherlands.
| | - Daniel S Olsson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Endocrinology at Sahlgrenska University Hospital, Gothenburg, Sweden
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Özcan B, Delhanty PJD, Huisman M, Visser JA, Neggers SJ, van der Lely AJ. Overweight and obesity in type 1 diabetes is not associated with higher ghrelin concentrations. Diabetol Metab Syndr 2021; 13:79. [PMID: 34294136 PMCID: PMC8296697 DOI: 10.1186/s13098-021-00699-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/09/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Several studies have demonstrated suppressed levels of acylated (AG) and unacylated ghrelin (UAG) in patients with type 2 diabetes. However, the role of these hormones in type 1 diabetes has not been extensively studied. This study assessed the relationship between AG and UAG levels and body composition in patients with type 1 diabetes. METHODS We selected eighteen patients with type 1 diabetes and divided them into two groups: non-obese (BMI < 25 kg/m2) and overweight (BMI ≥ 25 kg/m2). Demographics, parameters of body composition and serum parameters including AG and UAG, were assessed. RESULTS The patients with a BMI ≥ 25 kg/m2 were older and had a longer duration of diabetes. AG and UAG levels were not significantly different between non-obese and overweight groups (mean AG non-obese ± SD: 44.5 ± 29.4 pg/ml and mean UAG non-obese 42.4 ± 20.7 pg/ml vs mean AG overweight ± SD: 46.1 ± 29.6 pg/ml and mean UAG overweight 47.2 ± 18.2 pg/ml). AG/UAG ratios did not discriminate between these groups. There was a positive association of insuline dose/kg bodyweight with BMI (r2 = 0.45, p = 0.002). CONCLUSIONS Surprisingly, unlike non-diabetics and in T2D, we did not observe a difference in plasma levels of AG and UAG between normal weight and overweight adult type 1 diabetics. However, we did observe a positive correlation between BMI and insuline dose/kg bodyweight, suggesting that exogenous insulin is more important than the ghrelin system in the development of obesity in type 1 diabetes.
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Affiliation(s)
- Behiye Özcan
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
| | - Patric J D Delhanty
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Martin Huisman
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Jenny A Visser
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Sebastian J Neggers
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Aart Jan van der Lely
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
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Delhanty PJD, Huisman M, Prins K, Steenbergen C, Mies R, Neggers SJCMM, van der Lely AJ, Visser JA. Unacylated ghrelin binds heparan-sulfate proteoglycans which modulate its function. J Mol Endocrinol 2021; 66:83-96. [PMID: 33263557 DOI: 10.1530/jme-20-0286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/26/2020] [Indexed: 11/08/2022]
Abstract
Acylated ghrelin (AG) is a gut-derived peptide with growth hormone secretagogue (GHS), orexigenic and other physiological activities mediated by GHS receptor-1a (GHSR). Ghrelin occurs in unacylated form (UAG) with activities opposing AG, although its mechanism of action is unknown. UAG does not antagonize AG at GHSR, and has biological effects on cells that lack this receptor. Because UAG binds to cells, it has been hypothesized that UAG acts via a cell-surface receptor, although this has not been confirmed. This study aimed to identify cell surface proteins to which UAG binds that could modulate or mediate its biological effects. The MCF7 cell-line was used as a model because UAG induces ERK signaling in these cells in the absence of GHSR. Using ligand-receptor capture and LC-MS/MS we identified specific heparan-sulfate proteoglycans (HSPGs) to which UAG interacts on cell surfaces. In line with this, UAG, as well as AG, bind with high affinity to heparin, and heparin and heparinase treatment suppress, whereas HSPG overexpression increases, UAG binding to MCF7 cell surfaces. Moreover, heparin suppresses the ERK response to UAG. However, conversion of the lysines in UAG to alanine, which prevents its binding to heparin and cell surface HSPGs, does not prevent its activation of ERK. Our data show that the interaction of UAG with HSPGs modulates its biological activity in cells. More broadly, the interaction of UAG and AG with HSPGs could be important for the specificity and potency of their biological action in vivo.
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Affiliation(s)
- Patric J D Delhanty
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martin Huisman
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Karina Prins
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Cobie Steenbergen
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Rosinda Mies
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sebastian J C M M Neggers
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - A J van der Lely
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jenny A Visser
- Laboratory of Metabolism and Reproduction, Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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10
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Muhammad A, Coopmans EC, Delhanty PJD, Dallenga AHG, Haitsma IK, Janssen JAMJL, van der Lely AJ, Neggers SJCMM. Efficacy and Safety of switching to Pasireotide in Acromegaly Patients controlled with Pegvisomant and Somatostatin Analogues: PAPE extension study. Eur J Endocrinol 2018; 179:269-277. [PMID: 30076159 DOI: 10.1530/eje-18-0353] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/29/2018] [Accepted: 08/03/2018] [Indexed: 12/20/2022]
Abstract
OBJECTIVE to assess the efficacy and safety after 48 weeks of treatment with pasireotide long-acting-release (PAS-LAR) alone or in combination with pegvisomant in patients with acromegaly. In addition, we assessed the relation between insulin secretion and pasireotide-induced hyperglycemia. DESIGN The PAPE extension study is a prospective follow-up study until 48 weeks after the core study of 24 weeks. METHODS 59 out of 61 patients entered the extension study. Efficacy was defined as the percentage of patients achieving IGF-I normalization (≤ 1.2 x the Upper Limit of Normal (ULN)) at 48-weeks through protocol-based adjustment of pegvisomant and PAS-LAR doses. At baseline, insulin secretion was assessed by an oral glucose tolerance test (OGTT). RESULTS At the end of the study median IGF-I was 0.98 x ULN, and 77% of patients achieved normal IGF-I levels with a mean pegvisomant dose of 64 mg/week, and an overall cumulative pegvisomant dose reduction of 52%. Frequency of diabetes mellitus increased from 68% at 24 weeks to 77% at 48 weeks, and 9 patients discontinued PAS-LAR treatment, mainly because of severe hyperglycemia. Pasireotide-induced hyperglycemia was inversely correlated with baseline insulin secretion (r = -0.37, P < 0.005). CONCLUSIONS PAS-LAR normalizes IGF-I levels in most acromegaly patients, with a fifty percent pegvisomant-sparing effect. However, PAS-LAR treatment coincided with a high incidence of diabetes mellitus. The risk for developing diabetes during PAS-LAR treatment seems inversely related to insulin secretion at baseline.
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Affiliation(s)
| | | | | | - Alof H G Dallenga
- Department of Neurosurgery, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Iain K Haitsma
- Department of Neurosurgery, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, the Netherlands
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11
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Muhammad A, van der Lely AJ, Delhanty PJD, Dallenga AHG, Haitsma IK, Janssen JAMJL, Neggers SJCMM. Efficacy and Safety of Switching to Pasireotide in Patients With Acromegaly Controlled With Pegvisomant and First-Generation Somatostatin Analogues (PAPE Study). J Clin Endocrinol Metab 2018; 103:586-595. [PMID: 29155991 DOI: 10.1210/jc.2017-02017] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/10/2017] [Indexed: 11/19/2022]
Abstract
AIM To assess the efficacy and safety of pasireotide long-acting release (PAS-LAR) alone or in combination with pegvisomant by switching patients with acromegaly who were well controlled with long-acting somatostatin analogues (LA-SSAs) and pegvisomant to PAS-LAR with or without pegvisomant. METHODS Sixty-one patients with acromegaly were enrolled in a prospective open-label study. We included patients with an insulin-like growth factor I (IGF-I) ≤1.2 × upper limit of normal (ULN) during treatment with LA-SSAs and pegvisomant. At baseline, the pegvisomant dose was reduced by 50% up to 12 weeks. When IGF-I remained ≤1.2 × ULN after 12 weeks, patients were switched to PAS-LAR 60 mg monotherapy. When IGF-I was >1.2 × ULN, patients were switched to PAS-LAR 60 mg, and they continued with the 50% reduced pegvisomant dose. RESULTS At baseline, mean IGF-I was 0.97 × ULN, and the median pegvisomant dose was 80 mg/wk. At 12 weeks, mean IGF-I increased to 1.59 × ULN, and IGF-I levels ≤1.2 ULN were observed in 24.6% of participants. At 24 weeks, IGF-I levels were reduced into the reference range in 73.8% of patients. Between baseline and 24 weeks, the pegvisomant dose was reduced by 66.1%. PAS-LAR was well tolerated, but hyperglycemia was the most frequent adverse event. The frequency of diabetes increased from 32.8% at baseline to 68.9% at 24 weeks. CONCLUSIONS Switching to PAS-LAR, either as monotherapy or combination with pegvisomant, can control IGF-I levels in most patients. PAS-LAR demonstrated a pegvisomant-sparing effect of 66% compared with the combination with LA-SSAs. Hyperglycemia was the most important safety issue.
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Affiliation(s)
- Ammar Muhammad
- Department of Medicine, Endocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Aart J van der Lely
- Department of Medicine, Endocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Patric J D Delhanty
- Department of Medicine, Endocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Alof H G Dallenga
- Department of Neurosurgery, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Iain K Haitsma
- Department of Neurosurgery, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Joseph A M J L Janssen
- Department of Medicine, Endocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Sebastian J C M M Neggers
- Department of Medicine, Endocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
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12
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Brink HS, van der Lely AJ, Delhanty PJD, Huisman M, van der Linden J. Gestational diabetes mellitus and the ghrelin system. Diabetes Metab 2017; 45:393-395. [PMID: 29289478 DOI: 10.1016/j.diabet.2017.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 10/27/2017] [Accepted: 10/29/2017] [Indexed: 11/16/2022]
Affiliation(s)
- H S Brink
- Department of Internal Medicine, Maasstad Hospital, P.O. Box 9100, 3007, Rotterdam, CA, The Netherlands.
| | - A J van der Lely
- Department of Internal Medicine, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - P J D Delhanty
- Department of Internal Medicine, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - M Huisman
- Department of Internal Medicine, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - J van der Linden
- Department of Internal Medicine, Maasstad Hospital, P.O. Box 9100, 3007, Rotterdam, CA, The Netherlands
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13
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Muhammad A, Delhanty PJD, Huisman M, Visser JA, Jan van der Lelij A, Neggers SJCMM. The Acylated/Unacylated Ghrelin Ratio Is Similar in Patients With Acromegaly During Different Treatment Regimens. J Clin Endocrinol Metab 2017; 102:2425-2432. [PMID: 28402548 DOI: 10.1210/jc.2017-00147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/06/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Data on plasma acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in acromegaly are limited. High AG/UAG ratios are linked with type 2 diabetes, obesity, and hyperphagia (e.g., in Prader-Willi syndrome). OBJECTIVE To assess fasting plasma AG and UAG levels, and the AG/UAG ratio in acromegaly patients receiving combination treatment of long-acting somatostatin analogs (LA-SSAs) and pegvisomant (PEGV; n = 60). We used as controls acromegaly patients whose disease was controlled with PEGV monotherapy and medically naïve patients with active acromegaly. METHODS Fasting venous blood samples were collected and directly stabilized to inhibit deacylation of AG. Plasma AG and UAG levels were determined by double-antibody sandwich enzyme immunoassay, and the AG/UAG ratio was calculated. RESULTS Plasma AG and UAG levels were significantly lower in patients with acromegaly receiving combination treatment [median, interquartile range (IQR): AG: 8.5 pg/mL, 2.9 to 21.1 pg/mL; UAG: 26.9 pg/mL, 11.2 to 42.1 pg/mL] compared with patients using PEGV alone [AG: 60.5 pg/mL (IQR, 58.8 to 77.4 pg/mL); UAG: 153.7 pg/mL (IQR, 127.3 to 196.0 pg/mL)] and medically naïve patients with acromegaly [AG: 24.0 pg/mL (IQR, 12.6 to 49.7 pg/mL); UAG: 56.3 pg/mL (IQR, 43.4 to 61.5 pg/mL)]. However, AG/UAG ratios were similar in all groups. CONCLUSIONS Although plasma AG and UAG are suppressed during combination treatment with LA-SSAs and PEGV, the AG/UAG ratio remained similar. This shows that SSAs decrease both AG and UAG levels, which suggests that they do not alter metabolism significantly in acromegaly patients.
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Affiliation(s)
- Ammar Muhammad
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
| | - Patric J D Delhanty
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
| | - Jenny A Visser
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
| | - Aart Jan van der Lelij
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
| | - Sebastian J C M M Neggers
- Department of Internal Medicine, Section of Endocrinology, Erasmus University MC, 3000 CA Rotterdam, The Netherlands
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14
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Kuppens RJ, Delhanty PJD, Huisman TM, van der Lely AJ, Hokken-Koelega ACS. Acylated and unacylated ghrelin during OGTT in Prader-Willi syndrome: support for normal response to food intake. Clin Endocrinol (Oxf) 2016; 85:488-94. [PMID: 26850227 DOI: 10.1111/cen.13036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/20/2015] [Accepted: 02/02/2016] [Indexed: 01/13/2023]
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is characterized by hyperphagia with impaired satiety. PWS patients have very high acylated ghrelin (AG) with normal unacylated ghrelin (UAG) levels, resulting in an elevated AG/UAG ratio, suggesting an intrinsic defect in the ghrelin regulation. Normally, food intake induces satiety and a drop in AG and UAG levels, but it is unknown if these levels also decline in PWS. OBJECTIVE To evaluate whether the high AG levels in PWS decline in response to glucose intake during an oral glucose tolerance test (OGTT), and to investigate the effects of growth hormone (GH) treatment on this response. METHOD Serum levels of AG, UAG and AG/UAG ratio during an OGTT were determined in 24 GH-treated patients with PWS (median age 19·0, range 14·2-25·9 years) and in 10 GH-stop patients (of whom five were in GH-treated group; 18·5, 14·5-20·3 years). RESULTS In GH-treated and GH-stop young adults with PWS, there was a sharp decline of AG levels and a decrease of UAG levels in the first 30 min after the glucose load, which resulted in a lower AG/UAG ratio. GH-treated patients had significantly lower AG levels than GH-stop patients at baseline and during the OGTT. All UAG levels and AG/UAG ratios were lower in the GH-treated patients, although not significantly. CONCLUSIONS In young adults with PWS, an oral glucose load significantly reduces AG and UAG levels, suggesting normal regulation of the ghrelin axis by food intake. GH treatment results in lower AG levels at baseline and during OGTT, suggesting a more favourable metabolic profile. Our findings might suggest that the impaired satiety is not the result of an abnormal response of the orexigenic ghrelin to food intake.
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Affiliation(s)
- R J Kuppens
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
- Subdivision of Endocrinology, Department of Pediatrics, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - P J D Delhanty
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - T M Huisman
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A J van der Lely
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A C S Hokken-Koelega
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
- Subdivision of Endocrinology, Department of Pediatrics, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
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Kuppens RJ, Delhanty PJD, Huisman TM, van der Lely AJ, Hokken-Koelega ACS. The Authors' Reply: Acylated and unacylated ghrelin during OGTT in Prader-Willi syndrome, a rebuttal to the conclusions by Kuppens et al. Clin Endocrinol (Oxf) 2016; 85:323-4. [PMID: 27144882 DOI: 10.1111/cen.13091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R J Kuppens
- Dutch Growth Research Foundation, Rotterdam, The Netherlands. ,
- Erasmus University Medical Center-Sophia Children's Hospital, Department of Pediatrics, Subdivision of Endocrinology, Rotterdam, The Netherlands. ,
| | - P J D Delhanty
- Erasmus University Medical Center, Department of Internal Medicine, Rotterdam, The Netherlands
| | - T M Huisman
- Erasmus University Medical Center, Department of Internal Medicine, Rotterdam, The Netherlands
| | - A J van der Lely
- Erasmus University Medical Center, Department of Internal Medicine, Rotterdam, The Netherlands
| | - A C S Hokken-Koelega
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
- Erasmus University Medical Center-Sophia Children's Hospital, Department of Pediatrics, Subdivision of Endocrinology, Rotterdam, The Netherlands
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van Adrichem RCS, van der Lely AJ, Huisman M, Kramer P, Feelders RA, Delhanty PJD, de Herder WW. Plasma acylated and plasma unacylated ghrelin: useful new biomarkers in patients with neuroendocrine tumors? Endocr Connect 2016; 5:143-51. [PMID: 27215920 PMCID: PMC5002960 DOI: 10.1530/ec-16-0021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 05/23/2016] [Indexed: 12/18/2022]
Abstract
To date, the value of fasting plasma acylated ghrelin (AG) and unacylated ghrelin (UAG) as potential novel biomarkers in patients with neuroendocrine tumors (NETs) is unknown. The aims of this study are to (i) compare fasting AG and UAG levels between nonobese, nondiabetic NET patients (N=28) and age- (±3 years) and sex-matched nonobese, nondiabetic controls (N=28); and (ii) study the relationship between AG, UAG, and AG/UAG ratios and biochemical (chromogranin-A (CgA) and neuron-specific enolase (NSE) levels) and clinical parameters (age at diagnosis, sex, primary tumor location, carcinoid syndrome, ENETS TNM classification, Ki-67 proliferation index, grading, prior incomplete surgery) in NET patients. Fasting venous blood samples (N=56) were collected and directly stabilized with 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride after withdrawal. Plasma AG and UAG levels were determined by ELISA. Expression of ghrelin was examined in tumor tissue by immunohistochemistry. There were no significant differences between NET patients and controls in AG (median: 62.5 pg/mL, IQR: 33.1-112.8 vs median: 57.2pg/mL, IQR: 26.7-128.3, P=0.66) and UAG in levels (median: 76.6pg/mL, IQR: 35.23-121.7 vs median: 64.9, IQR: 27.5-93.1, P=0.44). No significant correlations were found between AG, UAG, and AG/UAG ratios versus biochemical and clinical parameters in NET patients with the exception of age at diagnosis (AG: ρ= -0.47, P=0.012; AG/UAG ratio: ρ= -0.50, P=0.007) and baseline chromogranin-A levels (AG/UAG ratio: ρ= -0.44, P=0.019). In our view, fasting plasma acylated and unacylated ghrelin appear to have no value as diagnostic biomarkers in the clinical follow-up of patients with NETs.
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Affiliation(s)
- Roxanne C S van Adrichem
- Department of Internal MedicineSector of Endocrinology, ENETS Centre of Excellence for Neuroendocrine Tumors, Erasmus MC, Rotterdam, The Netherlands
| | | | - Martin Huisman
- Department of Internal MedicineErasmus MC, Rotterdam, The Netherlands
| | - Piet Kramer
- Department of Internal MedicineErasmus MC, Rotterdam, The Netherlands
| | - Richard A Feelders
- Department of Internal MedicineSector of Endocrinology, ENETS Centre of Excellence for Neuroendocrine Tumors, Erasmus MC, Rotterdam, The Netherlands
| | | | - Wouter W de Herder
- Department of Internal MedicineSector of Endocrinology, ENETS Centre of Excellence for Neuroendocrine Tumors, Erasmus MC, Rotterdam, The Netherlands
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Kuppens RJ, Diène G, Bakker NE, Molinas C, Faye S, Nicolino M, Bernoux D, Delhanty PJD, van der Lely AJ, Allas S, Julien M, Delale T, Tauber M, Hokken-Koelega ACS. Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader-Willi syndrome. Endocrine 2015; 50:633-42. [PMID: 25989955 PMCID: PMC4662713 DOI: 10.1007/s12020-015-0614-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/21/2015] [Indexed: 01/13/2023]
Abstract
Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2-29.4 years) and compared with 50 age-matched obese subjects (4.3-16.9 years) and 39 healthy controls (0.8-28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.
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Affiliation(s)
- R J Kuppens
- Dutch Growth Research Foundation, Westzeedijk 106, 3016 AH, Rotterdam, The Netherlands.
- Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands.
| | - G Diène
- Unité D'endocrinologie, Obésité, Maladies Osseuses, Génétique et Gynécologie Médicale, Centre de Référence du Syndrome de Prader-Willi, Hôpital des enfants, Toulouse, France
| | - N E Bakker
- Dutch Growth Research Foundation, Westzeedijk 106, 3016 AH, Rotterdam, The Netherlands
- Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - C Molinas
- Unité D'endocrinologie, Obésité, Maladies Osseuses, Génétique et Gynécologie Médicale, Centre de Référence du Syndrome de Prader-Willi, Hôpital des enfants, Toulouse, France
- Axe pédiatrique du CIC 9302/INSERM. Hôpital des enfants, Toulouse, France
| | - S Faye
- Unité D'endocrinologie, Obésité, Maladies Osseuses, Génétique et Gynécologie Médicale, Centre de Référence du Syndrome de Prader-Willi, Hôpital des enfants, Toulouse, France
| | - M Nicolino
- Division of Pediatric Endocrinology, Hôpital Femme-Mère-Enfant, University of Lyon, Bron/Lyon, France
| | - D Bernoux
- Division of Pediatric Endocrinology, Hôpital Femme-Mère-Enfant, University of Lyon, Bron/Lyon, France
| | - P J D Delhanty
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A J van der Lely
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - S Allas
- Alizé Pharma, 69130, Ecully, France
| | - M Julien
- Alizé Pharma, 69130, Ecully, France
| | - T Delale
- Alizé Pharma, 69130, Ecully, France
| | - M Tauber
- Unité D'endocrinologie, Obésité, Maladies Osseuses, Génétique et Gynécologie Médicale, Centre de Référence du Syndrome de Prader-Willi, Hôpital des enfants, Toulouse, France
- INSERM U1043, Centre de Physiopathologie de Toulouse Purpan, Université Paul Sabatier, Toulouse, France
| | - A C S Hokken-Koelega
- Dutch Growth Research Foundation, Westzeedijk 106, 3016 AH, Rotterdam, The Netherlands
- Department of Pediatrics, Subdivision of Endocrinology, Erasmus University Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
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19
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Franck SE, van der Lely AJ, Delhanty PJD, Jørgensen JOL, Neggers SJCMM. Pegvisomant in combination with long-acting somatostatin analogues in acromegaly: the role of the GH receptor deletion of exon 3. Eur J Endocrinol 2015; 173:553-61. [PMID: 26243033 DOI: 10.1530/eje-15-0519] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/03/2015] [Indexed: 11/08/2022]
Abstract
BACKGROUND Doses of the GH receptor (GHR) antagonist pegvisomant (PEGV) that normalize insulin-like growth factor 1 (IGF1) levels vary widely among acromegaly patients. Predictors for PEGV response are baseline IGF1 levels, sex, body weight and previous radiotherapy. A GHR polymorphism lacking exon 3 (d3-GHR) is frequent in the general population. The influence of d3-GHR on PEGV responsiveness in acromegaly is unclear. OBJECTIVE To assess the influence of d3-GHR on IGF1 levels and PEGV responsiveness in acromegaly patients using combined PEGV and long-acting somatostatin receptor ligand (LA-SRIF) treatment. DESIGN Data were collected at the Rotterdam Pituitary Centre between 2004 and 2013. Patients with elevated IGF1 levels (>1.2 upper limit of normal; n=112) and over 6 months of high-dose LA-SRIF treatment were co-treated with PEGV. GHR genotype was assessed using genomic DNA in 104 patients. RESULTS D3-GHR was observed in 51 (49.0%) of the patients (7.7% homozygous, 41.3% heterozygous) and was in Hardy-Weinberg equilibrium (P=0.859). Baseline characteristics were similar in d3-GHR and full-length (fl)-GHR genotypes. During PEGV/LA-SRIF treatment IGF1 levels were not different between d3-carriers and non-carriers. Similarly, no difference in PEGV dose required to normalize IGF1 (P=0.337) or PEGV serum levels (P=0.433) was observed between the two groups. However, adenoma size decreased significantly (>20% of largest diameter) in 25.6% of the fl-GHR genotype but only in 7.5% of d3-carriers (P=0.034, OR: 4.6 (CI: 1.1-18.9)). CONCLUSIONS GHR genotype does not predict the IGF1 normalizing dose of PEGV in acromegaly patients using combination PEGV/LA-SRIF treatment. However, fewer d3-carriers showed significant reductions in adenoma size.
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Affiliation(s)
- S E Franck
- Department of Internal MedicineEndocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The NetherlandsDepartment of Internal MedicineEndocrinology Section, Medical Research Laboratories, Aarhus University Hospital, Aarhus, Denmark
| | - A J van der Lely
- Department of Internal MedicineEndocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The NetherlandsDepartment of Internal MedicineEndocrinology Section, Medical Research Laboratories, Aarhus University Hospital, Aarhus, Denmark
| | - P J D Delhanty
- Department of Internal MedicineEndocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The NetherlandsDepartment of Internal MedicineEndocrinology Section, Medical Research Laboratories, Aarhus University Hospital, Aarhus, Denmark
| | - J O L Jørgensen
- Department of Internal MedicineEndocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The NetherlandsDepartment of Internal MedicineEndocrinology Section, Medical Research Laboratories, Aarhus University Hospital, Aarhus, Denmark
| | - S J C M M Neggers
- Department of Internal MedicineEndocrinology Section, Pituitary Center Rotterdam, Erasmus University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, The NetherlandsDepartment of Internal MedicineEndocrinology Section, Medical Research Laboratories, Aarhus University Hospital, Aarhus, Denmark
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20
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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. Response to inquiry by Gaylinn et al. on 'Administration of UAG improves glycemic control in obese subjects with diabetes'. Eur J Endocrinol 2015; 173:L3-4. [PMID: 26026596 DOI: 10.1530/eje-15-0437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Behiye Özcan
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Sebastian J C M M Neggers
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Anne Reifel Miller
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Hsiu-Chiung Yang
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Virginia Lucaites
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Thierry Abribat
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Soraya Allas
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Martin Huisman
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Jenny A Visser
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Axel P N Themmen
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Eric J G Sijbrands
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Patric J D Delhanty
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Aart Jan van der Lely
- Department of MedicineErasmus University MC, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesEli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Delhanty PJD, van der Velde M, van der Eerden BCJ, Sun Y, Geminn JMM, van der Lely AJ, Smith RG, van Leeuwen JPTM. Genetic manipulation of the ghrelin signaling system in male mice reveals bone compartment specificity of acylated and unacylated ghrelin in the regulation of bone remodeling. Endocrinology 2014; 155:4287-95. [PMID: 25060361 DOI: 10.1210/en.2013-2055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Ghrelin receptor-deficient (Ghsr-/-) mice that lack acylated ghrelin (AG) signaling retain a metabolic response to unacylated ghrelin (UAG). Recently, we showed that Ghsr-deficiency affects bone metabolism. The aim of this study was to further establish the impact of AG and UAG on bone metabolism. We compared bone metabolism in Ghsr-/- (lacking only AG signaling) and ghrelin-deficient (Ghrl-/-; both AG and UAG deficient) male mice. Ghrl-/- mice had lower cortical bone mass, whereas Ghsr-/- mice had lower trabecular bone mass. This demonstrates bone compartment-specific effects of AG and a role for UAG in bone metabolism. Also, Ghrl-/- but not Ghsr-/- mice had increased bone formation rate and increased osteogenic stem cell numbers in their bone marrow. In ex vivo bone marrow cultures both AG and UAG inhibited osteoblast differentiation. This indicated that bone resorption must be increased in these mice. Accordingly, osteoclastogenesis rate was faster in bone marrow cultures from Ghsr-/- and Ghrl-/- mice, and osteoclast formation was inhibited by AG signaling and partially suppressed by UAG. In osteoblast cultures, AG markedly induced osteoprotegerin gene expression and both peptides reduced RANKL/osteoprotegerin ratio. These data describe unique cell-type specific effects of AG and UAG within a single tissue, supporting a tight and complex control of bone formation and resorption as well as a link between nutrition and bone metabolism. The balance between AG and UAG actions in the bone marrow may lead to bone compartmental-specific effects.
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Affiliation(s)
- Patric J D Delhanty
- Department of Internal Medicine (P.J.D.D., M.V.D.V., B.C.J.V.D.E., J.M.M.G., A.-J.V.D.L., J.P.T.M.V.L.), Erasmus MC, Postbus 2040, 3000 CA Rotterdam, The Netherlands; United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center (Y.S.) and Huffington Center on Aging, Baylor College of Medicine, Houston, Texas 77030; and Department of Metabolism and Aging (R.G.S.), The Scripps Research Institute Florida, Jupiter, Florida 33458
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23
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Delhanty PJD, Bouw E, Huisman M, Vervenne RML, Themmen APN, van der Lely AJ, van den Akker ELT. Functional characterization of a new human melanocortin-4 receptor homozygous mutation (N72K) that is associated with early-onset obesity. Mol Biol Rep 2014; 41:7967-72. [PMID: 25163632 DOI: 10.1007/s11033-014-3691-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 08/21/2014] [Indexed: 01/31/2023]
Abstract
The melanocortin 4 receptor (MC4R) is expressed in the hypothalamus and is essential for regulation of appetite and energy expenditure. MC4R dysfunction in humans causes hyperphagia, impaired satiety and obesity. We have identified a novel c.216C>A (N72 K) homozygous mutation in MC4R in a girl with severe obesity. The patient presented with early-onset obesity and hyperphagia indicating an effect of the homozygous mutation on her phenotype. In silico analyses indicate a damaging effect on receptor function, and the mutation is unusual in occurring in the first intra-cellular loop of the receptor. Site-directed mutagenesis was used to generate plasmid constructs expressing wild-type and mutant MC4R. These were transfected into HEK293 cells and assessed for cAMP responsiveness to α-MSH. Cells expressing N-terminal HA and C-terminal GFP-tagged MC4R were assessed by immunofluorescence confocal microscopy and flow cytometry for correct cell-surface localization. The maximal response of the mutant MC4R to α-MSH was decreased to 20 ± 1 % of the wild type receptor response, and the EC50 was increased from 16.5 ± 5.4 nM to 37.0 ± 8.3 nM. Localization of N- and C-terminally tagged MC4R by confocal microscopy and flow cytometry showed aberrant retention of the mutant receptor in the cytoplasm. Our data describe a rare homozygous inactivating mutation in the first intra-cellular loop of MC4R that markedly impairs its function and is associated with early-onset obesity and hyperphagia.
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Affiliation(s)
- Patric J D Delhanty
- Departments of Internal Medicine and Pediatric Endocrinology, Erasmus MC, Rotterdam, The Netherlands,
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24
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Bouw E, Huisman M, Neggers SJCMM, Themmen APN, van der Lely AJ, Delhanty PJD. Development of potent selective competitive-antagonists of the melanocortin type 2 receptor. Mol Cell Endocrinol 2014; 394:99-104. [PMID: 25017734 DOI: 10.1016/j.mce.2014.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/16/2014] [Accepted: 07/03/2014] [Indexed: 11/16/2022]
Abstract
Cushing's disease, a hypercortisolemic state induced by an ACTH overexpressing pituitary adenoma, causes increased morbidity and mortality. Selective antagonism of the melanocortin type 2 receptor (MC2R) may be a novel treatment modality. Five structurally related peptides with modified HFRW sites but intact putative MC2R binding sites were tested for antagonistic activity at MC1R, MC2R/MRAP, MC3R, MC4R and MC5R. Two of these peptides (GPS1573 and GPS1574) dose-dependently antagonized ACTH-stimulated MC2R activity (IC50s of 66±23 nM and 260±1 nM, respectively). GPS1573 and 1574 suppressed the Rmax but not EC50 of ACTH on MC2R, indicating non-competitive antagonism. These peptides did not antagonize α-MSH stimulation of MC1R and antagonized MC3, 4 and 5R at markedly lower potency. GP1573 and GPS1574 antagonize MC4R with IC50s of 950 nM and 3.7 μM, respectively. In conclusion, two peptide antagonists were developed with selectivity for MC2R, forming a platform for development of a medical treatment for Cushing's disease.
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MESH Headings
- Adrenocorticotropic Hormone/genetics
- Adrenocorticotropic Hormone/metabolism
- Adrenocorticotropic Hormone/pharmacology
- Amino Acid Sequence
- Dose-Response Relationship, Drug
- Drug Design
- Gene Expression
- HEK293 Cells
- Humans
- Molecular Sequence Data
- Peptides/chemical synthesis
- Peptides/pharmacology
- Pituitary ACTH Hypersecretion/drug therapy
- Protein Binding
- Receptor, Melanocortin, Type 1/chemistry
- Receptor, Melanocortin, Type 1/genetics
- Receptor, Melanocortin, Type 1/metabolism
- Receptor, Melanocortin, Type 2/antagonists & inhibitors
- Receptor, Melanocortin, Type 2/chemistry
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptor, Melanocortin, Type 3/chemistry
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/chemistry
- Receptors, Melanocortin/genetics
- Receptors, Melanocortin/metabolism
- Structure-Activity Relationship
- Transfection
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Affiliation(s)
- Elise Bouw
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | | | - Axel P N Themmen
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - A J van der Lely
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Patric J D Delhanty
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
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25
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Stevanovic DM, Grefhorst A, Themmen APN, Popovic V, Holstege J, Haasdijk E, Trajkovic V, van der Lely AJ, Delhanty PJD. Unacylated ghrelin suppresses ghrelin-induced neuronal activity in the hypothalamus and brainstem of male rats [corrected]. PLoS One 2014; 9:e98180. [PMID: 24852945 PMCID: PMC4031147 DOI: 10.1371/journal.pone.0098180] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/29/2014] [Indexed: 01/03/2023] Open
Abstract
Ghrelin, the endogenous growth hormone secretagogue, has an important role in metabolic homeostasis. It exists in two major molecular forms: acylated (AG) and unacylated (UAG). Many studies suggest different roles for these two forms of ghrelin in energy balance regulation. In the present study, we compared the effects of acute intracerebroventricular administration of AG, UAG and their combination (AG+UAG) to young adult Wistar rats on food intake and central melanocortin system modulation. Although UAG did not affect food intake it significantly increased the number of c-Fos positive neurons in the arcuate (ARC), paraventricular (PVN) and solitary tract (NTS) nuclei. In contrast, UAG suppressed AG-induced neuronal activity in PVN and NTS. Central UAG also modulated hypothalamic expression of Mc4r and Bmp8b, which were increased and Mc3r, Pomc, Agrp and Ucp2, which were decreased. Finally, UAG, AG and combination treatments caused activation of c-Fos in POMC expressing neurons in the arcuate, substantiating a physiologic effect of these peptides on the central melanocortin system. Together, these results demonstrate that UAG can act directly to increase neuronal activity in the hypothalamus and is able to counteract AG-induced neuronal activity in the PVN and NTS. UAG also modulates expression of members of the melanocortin signaling system in the hypothalamus. In the absence of an effect on energy intake, these findings indicate that UAG could affect energy homeostasis by modulation of the central melanocortin system.
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Affiliation(s)
- Darko M. Stevanovic
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
- Institute of Medical Physiology, School of Medicine, University of Belgrade, Belgrade, Serbia
- * E-mail: (DS); (PJDD)
| | - Aldo Grefhorst
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Axel P. N. Themmen
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Vera Popovic
- Institute of Endocrinology, Diabetes and Diseases of Metabolism, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Joan Holstege
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Elize Haasdijk
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Vladimir Trajkovic
- Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Patric J. D. Delhanty
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
- * E-mail: (DS); (PJDD)
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Abstract
Ghrelin is a gut-derived peptide hormone, first isolated from the stomach. Ghrelin was initially characterized as a growth hormone (GH) secretagogue, but it plays a more important role as a potent orexigen and modulator of whole-body energy homeostasis. Ghrelin itself is closely regulated by metabolic status. Bone remodeling constantly renews the skeleton in a highly energy-dependent fashion. Accordingly, bone metabolism is tightly coupled to energy metabolism through the integration of peripheral and central mechanisms, involving the sympathetic nervous system and factors such as leptin. Ghrelin has been shown to modulate osteoblast differentiation and function, both directly and perhaps also through regulation of the GH-insulin-like growth factor axis. However, recently it has also been shown that ghrelin interacts with leptin in modulating bone structure, constituting a new mechanism that couples bone metabolism with energy homeostasis. In this review, we discuss the role that ghrelin plays modulating bone cell function, and its integrative role in coupling bone metabolism with energy metabolism.
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Blijdorp K, van der Lely AJ, van den Heuvel-Eibrink MM, Huisman TM, Themmen APN, Delhanty PJD, Neggers SJCMM. Desacyl ghrelin is influenced by changes in insulin concentration during an insulin tolerance test. Growth Horm IGF Res 2013; 23:193-195. [PMID: 23850060 DOI: 10.1016/j.ghir.2013.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 06/12/2013] [Accepted: 06/20/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Ghrelin, a gut-brain peptide, regulates energy homeostasis and glucose metabolism and is present in acylated and nonacylated form in the circulation. Although desacyl ghrelin (DAG), the predominant form of ghrelin, is associated with insulin sensitivity and improved metabolic state, not much is known about its direct regulation by insulin. We aimed to assess changes in DAG in response to the rapid increase in insulin concentration during an insulin tolerance test (ITT) in normal weight and obese subjects. DESIGN We performed an observational single center study. An ITT was assessed in eight subjects (four males), median age of 29.9 years (range 19.6-42.0). DAG concentrations were measured at 20, 40, 60 and 90 min after insulin infusion. Homeostatic Model Assessment (HOMA) was calculated from fasting insulin and glucose. Body mass index (BMI) and waist circumference were assessed. RESULTS Three subjects were obese (BMI ≥ 30 kg/m(2)), one subject was overweight (BMI = 25-30 kg/m(2)) and four subjects had normal weight (BMI = 18.5-25 kg/m(2)). Median DAG decreased after insulin infusion (90 pg/mL, p = 0.028), especially in normal weight subjects. Baseline DAG was lower in subjects with higher BMI (ρ = -0.76, p = 0.028) and higher fasting insulin (ρ = -0.76, p = 0.030). DAG changes correlated with fasting insulin levels (ρ = -0.85, p = 0.007), HOMA (ρ = -0.86, p = 0.007), BMI (ρ = -0.83, p = 0.010) and waist circumference (ρ = -0.93, p < 0.001). CONCLUSION DAG levels rapidly decreased in response to insulin administration in normal subjects, but not in insulin-resistant obese who are in a state of relative DAG deficiency.
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Affiliation(s)
- K Blijdorp
- Department of Medicine - section Endocrinology, Erasmus University Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
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Delhanty PJD, Huisman M, Baldeon-Rojas LY, van den Berge I, Grefhorst A, Abribat T, Leenen PJM, Themmen APN, van der Lely AJ. Des-acyl ghrelin analogs prevent high-fat-diet-induced dysregulation of glucose homeostasis. FASEB J 2013; 27:1690-700. [PMID: 23299855 DOI: 10.1096/fj.12-221143] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There is clinical evidence that des-acyl ghrelin (DAG) favorably modulates glucose and lipid metabolism, although its mode of action is unknown. A murine model of prediabetes was used to assess possible mechanisms of action for DAG and a newly developed bioactive analog, AZP531. C57BL/6J mice were infused with saline, DAG, or AZP531 continuously for 4 wk, and fed either normal diet (ND) or normal diet for 2 wk followed by a high-fat diet (HFD) for 2 wk. Compared with mice in the ND group, HFD increased body and fat mass, caused glucose intolerance and insulin resistance, had proinflammatory effects in white adipose tissue, and caused lipid accumulation in brown adipose tissue. DAG and AZP531 treatment prevented HFD-induced proinflammatory effects, stimulated expression of mitochondrial function markers in brown adipose tissue, and prevented development of a prediabetic metabolic state. AZP531 also prevented a HFD-induced increase in acyl ghrelin levels. Our data indicate DAG analogs as potential treatment for the prevention of metabolic syndrome.
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Affiliation(s)
- Patric J D Delhanty
- Dept. of Internal Medicine, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
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Abstract
Des-acyl ghrelin (DAG) is one of the three preproghrelin gene-encoded peptides. Compared with ghrelin and obestatin, it has not received the attention it deserves. DAG has long been considered an inert degradation product of acyl ghrelin (AG). Recent evidence, however, indicates that DAG behaves like a separate hormone. DAG can act together with AG, can antagonize AG, and seems to have AG-independent effects. Therefore, it is believed that DAG must activate its own receptor and that it may also interact with AG at this receptor. Of potential clinical importance is that an increasing number of studies suggest that DAG might be a functional inhibitor of ghrelin and that DAG can suppress ghrelin levels in humans. Therefore, DAG or DAG analogs might be good candidates for future treatment of metabolic disorders or other conditions in which antagonism of AG actions could be beneficial, such as diabetes, obesity, and Prader-Willi syndrome.
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Affiliation(s)
- Patric J D Delhanty
- Department of Medicine, Erasmus University MC, CA Rotterdam, The Netherlands
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van der Velde M, van der Eerden BCJ, Sun Y, Almering JMM, van der Lely AJ, Delhanty PJD, Smith RG, van Leeuwen JPTM. An age-dependent interaction with leptin unmasks ghrelin's bone-protective effects. Endocrinology 2012; 153:3593-602. [PMID: 22700774 PMCID: PMC5393325 DOI: 10.1210/en.2012-1277] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mutual interplay between energy homeostasis and bone metabolism is an important emerging concept. Ghrelin and leptin antagonize each other in regulating energy balance, but the role of this interaction in bone metabolism is unknown. Using ghrelin receptor and leptin-deficient mice, we show that ghrelin has dual effects on osteoclastogenesis, inhibiting osteoclast progenitors directly and stimulating osteoclastogenesis via a more potent systemic/central pathway. Using mice with combined ghrelin receptor and leptin deficiency, we find that this systemic osteoclastogenic activity is suppressed by leptin, thus balancing the two counterregulatory ghrelin pathways and leading to an unchanged bone structure. With aging, this osteoclastogenic ghrelin pathway is lost, unmasking the direct protective effect of ghrelin on bone structure. In conclusion, we identify a novel regulatory network linking orexigenic and anorectic metabolic factors with bone metabolism that is age dependent.
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Affiliation(s)
- Martijn van der Velde
- Department of Internal Medicine, Erasmus University Medical Center's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
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Julien M, Kay RG, Delhanty PJD, Allas S, Granata R, Barton C, Constable S, Ghigo E, van der Lely AJ, Abribat T. In vitro and in vivo stability and pharmacokinetic profile of unacylated ghrelin (UAG) analogues. Eur J Pharm Sci 2012; 47:625-35. [PMID: 22841845 DOI: 10.1016/j.ejps.2012.07.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 12/01/2022]
Abstract
Ghrelin, an endocrine hormone predominantly produced by the stomach, exists in acylated and unacylated forms in the circulation. Unacylated ghrelin (UAG), the more abundant form in blood, possesses similar, independent or opposite physiological actions as acylated ghrelin (AG). AZP502, a linear 8-amino acid peptide from the central region of UAG (UAG(6-13)), and its full (AZP531) and partially (AZP533) cyclised derivatives, exhibit the same pharmacological profile as UAG both in vitro and in vivo, independently of AG receptor binding. We investigated the stability of these three fragments in vitro in human blood samples and in vivo after subcutaneous and intravenous injection in rats and dogs using liquid chromatography-mass spectrometry. In both species, AZP502 is rapidly degraded generating two major metabolites. Partial cyclisation of AZP502 and acylation at its N-terminus (AZP533 peptide) improves its stability in human plasma in vitro. Full cyclisation of AZP502 (AZP531 peptide) also completely protects the peptide from peptidase degradation in vitro in human blood samples. Moreover this cyclisation strongly improves the stability and the bioavailability of this peptide in vivo in both dogs and rats (mean bioavailability of 10-15% and 85-95% for AZP502 and AZP531 respectively). Taken together these results support the rationale for developing AZP531 as a long-acting UAG analogue for subcutaneous injection for the treatment of type 2 diabetes mellitus and other metabolic disorders.
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Affiliation(s)
- Michel Julien
- Alizé Pharma SAS, 15 Chemin du Saquin, Espace Européen, Building G, 69130 Ecully, France.
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Abstract
Ghrelin plays an important physiological role in modulating GH secretion, insulin secretion and glucose metabolism. Ghrelin has direct effects on pancreatic islet function. Also, ghrelin is part of a mechanism that integrates the physiological response to fasting. However, pharmacologic studies indicate the important obesogenic/diabetogenic properties of ghrelin. This is very likely of physiological relevance, deriving from a requirement to protect against seasonal periods of food scarcity by building energy reserves, predominantly in the form of fat. Available data indicate the potential of ghrelin blockade as a means to prevent its diabetogenic effects. Several studies indicate a negative correlation between ghrelin levels and the incidence of type 2 diabetes and insulin resistance. However, it is unclear if low ghrelin levels are a risk factor or a compensatory response. Direct antagonism of the receptor does not always have the desired effects, however, since it can cause increased body weight gain. Pharmacological suppression of the ghrelin/des-acyl ghrelin ratio by treatment with des-acyl ghrelin may also be a viable alternative approach which appears to improve insulin sensitivity. A promising recently developed approach appears to be through the blockade of GOAT activity, although the longer term effects of this treatment remain to be investigated.
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Affiliation(s)
- P J D Delhanty
- Department of Internal Medicine, Erasmus MC, 3000 CA Rotterdam, The Netherlands.
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van Ginhoven TM, Huisman TM, van den Berg JW, Ijzermans JNM, Delhanty PJD, de Bruin RWF. Preoperative fasting induced protection against renal ischemia/reperfusion injury is independent of ghrelin in mice. Nutr Res 2011; 30:865-9. [PMID: 21147370 DOI: 10.1016/j.nutres.2010.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 10/18/2022]
Abstract
One of the factors negatively influencing the outcome after kidney transplantation is ischemia-reperfusion (I/R) injury. Preoperative fasting is able to confer protection against I/R injury. We hypothesized that the protection imposed by preoperative fasting is mediated by increased levels of acylated ghrelin. Male C57BL/6 mice, 10 to 12 weeks old, were fasted for 1, 2, or 3 days, after which, acylated ghrelin levels were determined. Ad libitum fed mice were injected with acylated ghrelin or phosphate-buffered saline before renal I/R injury. Furthermore, mice were fasted for 3 days during which they were injected with a growth hormone secretagogue receptor antagonist, to block the effects of ghrelin, or a vehiculum. Bilateral renal I/R injury was induced by clamping the artery and vein of the left and right kidney simultaneously for 37 minutes. Kidney function was assessed by means of serum urea values determined at 24 and 48 hours after reperfusion. Fasting significantly increased acylated ghrelin serum levels. Ghrelin suppletion in ad libitum fed animals or ghrelin receptor blockade in fasted animals did not affect renal function after I/R injury. Our data suggest that the increased levels of acylated ghrelin induced by fasting do not mediate its protection against renal I/R injury.
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Delhanty PJD, van Kerkwijk A, Huisman M, van de Zande B, Verhoef-Post M, Gauna C, Hofland L, Themmen APN, van der Lely AJ. Unsaturated fatty acids prevent desensitization of the human growth hormone secretagogue receptor by blocking its internalization. Am J Physiol Endocrinol Metab 2010; 299:E497-505. [PMID: 20587751 DOI: 10.1152/ajpendo.00414.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The composition of the plasma membrane affects the responsiveness of cells to metabolically important hormones such as insulin and vasoactive intestinal peptide. Ghrelin is a metabolically regulated hormone that activates the G protein-coupled receptor GH secretagogue receptor type 1a (GHSR) not only in the pituitary gland but also in peripheral tissues such as the pancreas, stomach, and T cells in the circulation. We have investigated the effects of lipids and altered plasma membrane composition on GHSR activation. Oligounsaturated fatty acids (OFAs) disrupt the structure of membranes and make them more fluid. Prolonged (96 h), but not acute, treatment of the GHSR cells with the 18C OFAs oleic and linoleic acid caused a significant increase in sensitivity of the receptor to ghrelin (EC(50) reduced by a factor of 2.4 and 2.9 at 60 and 120 microM OFAs, respectively). OFAs were found to block the inhibitory effects of ghrelin pretreatment on subsequent ghrelin responsiveness, suggesting that OFAs suppress desensitization of GHSR. Radioligand displacement studies did not show a significant shift in receptor binding after incubation with OFAs. However, it was found that OFA treatment suppressed GHSR internalization, likely explaining OFA-induced refractoriness to ligand-induced desensitization. The involvement of lipid rafts in this process was indicated by the altered responsiveness of GHSR under conditions that alter membrane cholesterol. In conclusion, our findings demonstrate the importance of membrane composition for GHSR activation and desensitization and indicate at least part of the mechanism through which OFAs and cholesterol could affect ghrelin's activity in vivo.
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Affiliation(s)
- Patric J D Delhanty
- Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands.
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Delhanty PJD, Sun Y, Visser JA, van Kerkwijk A, Huisman M, van Ijcken WFJ, Swagemakers S, Smith RG, Themmen APN, van der Lely AJ. Unacylated ghrelin rapidly modulates lipogenic and insulin signaling pathway gene expression in metabolically active tissues of GHSR deleted mice. PLoS One 2010; 5:e11749. [PMID: 20668691 PMCID: PMC2909919 DOI: 10.1371/journal.pone.0011749] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 06/12/2010] [Indexed: 12/25/2022] Open
Abstract
Background There is increasing evidence that unacylated ghrelin (UAG) improves insulin sensitivity and glucose homeostasis; however, the mechanism for this activity is not fully understood since a UAG receptor has not been discovered. Methodology/Principal Findings To assess potential mechanisms of UAG action in vivo, we examined rapid effects of UAG on genome-wide expression patterns in fat, muscle and liver of growth hormone secretagogue receptor (GHSR)-ablated mice using microarrays. Expression data were analyzed using Ingenuity Pathways Analysis and Gene Set Enrichment Analysis. Regulation of subsets of these genes was verified by quantitative PCR in an independent experiment. UAG acutely regulated clusters of genes involved in glucose and lipid metabolism in all three tissues, consistent with enhancement of insulin sensitivity. Conclusions/Significance Fat, muscle and liver are central to the control of lipid and glucose homeostasis. UAG rapidly modulates the expression of metabolically important genes in these tissues in GHSR-deleted mice indicating a direct, GHSR-independent, action of UAG to improve insulin sensitivity and metabolic profile.
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Kiewiet RM, van Aken MO, van der Weerd K, Uitterlinden P, Themmen APN, Hofland LJ, de Rijke YB, Delhanty PJD, Ghigo E, Abribat T, van der Lely AJ. Effects of acute administration of acylated and unacylated ghrelin on glucose and insulin concentrations in morbidly obese subjects without overt diabetes. Eur J Endocrinol 2009; 161:567-73. [PMID: 19628651 DOI: 10.1530/eje-09-0339] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To investigate the effects of unacylated ghrelin (UAG) and co-administration of acylated ghrelin (AG) and UAG in morbid obesity, a condition characterized by insulin resistance and low GH levels. DESIGN AND METHOD Eight morbidly obese non-diabetic subjects were treated with either UAG 200 microg, UAG 100 microg in combination with AG 100 microg (Comb) or placebo in three episodes of 4 consecutive days in a double-blind randomized crossover design. Study medication was administered as daily single i.v. bolus injections at 0900 h after an overnight fast. At 1000 h, a standardized meal was served. Glucose, insulin, GH, free fatty acids (FFA) and ghrelin were measured up to 4 h after administration. RESULTS Insulin concentrations significantly decreased after acute administration of Comb only, reaching a minimum at 20 min: 58.2 + or - 3.9% of baseline versus 88.7 + or - 7.2 and 92.7 + or - 2.6% after administration of placebo and UAG respectively (P<0.01). After 1 h, insulin concentration had returned to baseline. Glucose concentrations did not change after Comb. However, UAG administration alone did not change glucose, insulin, FFA or GH levels. CONCLUSION Co-administration of AG and UAG as a single i.v. bolus injection causes a significant decrease in insulin concentration in non-diabetic subjects suffering from morbid obesity. Since glucose concentration did not change in the first hour after Comb administration, our data suggest a strong improvement in insulin sensitivity. These findings warrant studies in which UAG with or without AG is administered for a longer period of time. Administration of a single bolus injection of UAG did not influence glucose and insulin metabolism.
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Affiliation(s)
- Rosalie M Kiewiet
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, Molinette Hospital, Corso Dogliotti 14, 10126, Turin, Italy.
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Gauna C, Uitterlinden P, Kramer P, Kiewiet RM, Janssen JAMJL, Delhanty PJD, van Aken MO, Ghigo E, Hofland LJ, Themmen APN, van der Lely AJ. Intravenous glucose administration in fasting rats has differential effects on acylated and unacylated ghrelin in the portal and systemic circulation: a comparison between portal and peripheral concentrations in anesthetized rats. Endocrinology 2007; 148:5278-87. [PMID: 17673520 DOI: 10.1210/en.2007-0225] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Ghrelin is produced by the gastrointestinal tract, and its systemic concentrations are mainly regulated by nutritional factors. Our aim was to investigate: 1) endogenous portal and systemic acylated and unacylated ghrelin levels (AG and UAG, respectively); 2) whether an iv glucose tolerance test (IVGTT) modifies AG and UAG; and 3) whether the liver passage plays a role in regulating systemic AG and UAG. To elucidate this, we evaluated the effects of IVGTT or saline injection on endogenous portal and systemic concentrations of glucose, insulin, AG, and UAG in anesthetized fasting rats. Hepatic extraction of insulin, AG, and UAG and the ratio of AG to UAG were also measured. IVGTT suppressed both portal (P < 0.03) and peripheral (P < 0.05) UAG, whereas it only blunted prehepatic, but not peripheral, AG. During fasting, hepatic clearance of UAG was 11%, and it was decreased to 8% by IVGTT. AG was cleared by the liver by 38% but unaffected by glucose. The AG to UAG ratio was higher in the portal than the systemic circulation, both in the saline (P < 0.004) and IVGTT (P < 0.0005) rats. In conclusion, this study shows that: 1) the ratio of AG to UAG is very low in the portal vein and decreases further in the systemic circulation; 2) IVGTT in anesthetized fasting rats inhibits UAG, whereas it only blunts prehepatic, but not systemic, AG; and 3) hepatic clearance of AG is much higher than that of UAG. Thus, our results suggest that peripheral AG metabolic regulation and action are mainly confined within the gastrointestinal tract.
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Affiliation(s)
- Carlotta Gauna
- Division of Endocrinology, Department of Internal Medicine, Room Ee542, Erasmus Medical Center, Dr Molewaterplein 50, 3015 GE, Rotterdam, The Netherlands.
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Gauna C, Kiewiet RM, Janssen JAMJL, van de Zande B, Delhanty PJD, Ghigo E, Hofland LJ, Themmen APN, van der Lely AJ. Unacylated ghrelin acts as a potent insulin secretagogue in glucose-stimulated conditions. Am J Physiol Endocrinol Metab 2007; 293:E697-704. [PMID: 17578884 DOI: 10.1152/ajpendo.00219.2007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Acylated and unacylated ghrelin (AG and UAG) are gut hormones that exert pleiotropic actions, including regulation of insulin secretion and glucose metabolism. In this study, we investigated whether AG and UAG differentially regulate portal and systemic insulin levels after a glucose load. We studied the effects of the administration of AG (30 nmol/kg), UAG (3 and 30 nmol/kg), the ghrelin receptor antagonist [D-Lys(3)]GHRP-6 (1 micromol/kg), or various combinations of these compounds on portal and systemic levels of glucose and insulin after an intravenous glucose tolerance test (IVGTT, d-glucose 1 g/kg) in anesthetized fasted Wistar rats. UAG administration potently and dose-dependently enhanced the rise of insulin concentration induced by IVGTT in the portal and, to a lesser extent, the systemic circulation. This UAG-induced effect was completely blocked by the coadministration of exogenous AG at equimolar concentrations. Similarly to UAG, [D-Lys(3)]GHRP-6, alone or in combination with AG and UAG, strongly enhanced the portal insulin response to IVGTT, whereas exogenous AG alone did not exert any further effect. Our data demonstrate that, in glucose-stimulated conditions, exogenous UAG acts as a potent insulin secretagogue, whereas endogenous AG exerts a maximal tonic inhibition on glucose-induced insulin release.
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Affiliation(s)
- Carlotta Gauna
- Division of Endocrinology, Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands.
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Gauna C, van de Zande B, van Kerkwijk A, Themmen APN, van der Lely AJ, Delhanty PJD. Unacylated ghrelin is not a functional antagonist but a full agonist of the type 1a growth hormone secretagogue receptor (GHS-R). Mol Cell Endocrinol 2007; 274:30-4. [PMID: 17601657 DOI: 10.1016/j.mce.2007.05.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 05/07/2007] [Accepted: 05/16/2007] [Indexed: 10/23/2022]
Abstract
Recent findings demonstrate that the effects of ghrelin can be abrogated by co-administered unacylated ghrelin (UAG). Since the general consensus is that UAG does not interact with the type 1a growth hormone secretagogue receptor (GHS-R), a possible mechanism of action for this antagonistic effect is via another receptor. However, functional antagonism of the GHS-R by UAG has not been explored extensively. In this study we used human GHS-R and aequorin expressing CHO-K1 cells to measure [Ca(2+)](i) following treatment with UAG. UAG at up to 10(-5)M did not antagonize ghrelin induced [Ca(2+)](i). However, UAG was found to be a full agonist of the GHS-R with an EC(50) of between 1.6 and 2 microM using this in vitro system. Correspondingly, UAG displaced radio-labeled ghrelin from the GHS-R with an IC(50) of 13 microM. In addition, GHS-R antagonists were found to block UAG induced [Ca(2+)](i) with approximately similar potency to their effect on ghrelin activation of the GHS-R, suggesting a similar mode of action. These findings demonstrate in a defined system that UAG does not antagonize activation of the GHS-R by ghrelin. But our findings also emphasize the importance of assessing the concentration of UAG used in both in vitro and in vivo experimental systems that are aimed at examining GHS-R independent effects. Where local concentrations of UAG may reach the high nanomolar to micromolar range, assignment of GHS-R independent effects should be made with caution.
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Affiliation(s)
- Carlotta Gauna
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
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Delhanty PJD, van Koetsveld PM, Gauna C, van de Zande B, Vitale G, Hofland LJ, van der Lely AJ. Ghrelin and its unacylated isoform stimulate the growth of adrenocortical tumor cells via an anti-apoptotic pathway. Am J Physiol Endocrinol Metab 2007; 293:E302-9. [PMID: 17405826 DOI: 10.1152/ajpendo.00377.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ghrelin is expressed in normal human adrenocortical cells and induces their proliferation through growth hormone secretagogue receptor 1a (GHS-R1a). Consequently, it was of interest to us to determine whether acylated ghrelin and its predominant serum isoform, unacylated ghrelin, also act as factors for adrenocortical carcinoma cell growth. To examine a potential ghrelin-regulated system in adrenocortical tumors, we measured proliferative effects of acylated and unacylated ghrelin in the adrenocortical carcinoma cell lines SW-13 and NCI-H295R. We also examined the expression of ghrelin, GHS-R1a, and corticotrophin-releasing factor receptor 2 (CRF-R2). Acylated and unacylated ghrelin in the nanomolar range dose-dependently induced adrenocortical cell growth up to 200% of untreated controls, as measured by thymidine uptake and WST1 assay. The proliferative effects of acylated and unacylated ghrelin in SW-13 cells was blocked by [D-Lys(3)]growth hormone-releasing peptide 6 (GHRP6), but a CRF-R2 antagonist had no effect on unacylated ghrelin growth stimulation. Cell cycle analysis suggests that acylated and unacylated ghrelin suppress the sub-G(0)/apoptotic fraction by up to 50%. Measurement of DNA fragmentation and caspase-3 and -7 activity in SW-13 cells confirmed that acylated and unacylated ghrelin suppress apoptotic rate. SW-13 cells express preproghrelin mRNA and secrete ghrelin, and [D-Lys(3)]GHRP6 suppresses their basal proliferation rate, strongly suggesting that ghrelin could act as an auto/paracrine growth factor. Acylated and unacylated ghrelin are potential auto/paracrine factors acting through an antiapoptotic pathway to stimulate adrenocortical tumor cell growth. Unacylated ghrelin-stimulated growth is suppressed by an antagonist of GHS-R1a, suggesting either that unacylated ghrelin is acylated before its action or that ghrelin, unacylated ghrelin, and [D-Lys(3)]GHRP-6 bind to a novel receptor in these cells.
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Affiliation(s)
- P J D Delhanty
- Department of Internal Medicine, Rm. Ee542, Erasmus Medical Centre, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands.
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Gauna C, Delhanty PJD, van Aken MO, Janssen JAMJL, Themmen APN, Hofland LJ, Culler M, Broglio F, Ghigo E, van der Lely AJ. Unacylated ghrelin is active on the INS-1E rat insulinoma cell line independently of the growth hormone secretagogue receptor type 1a and the corticotropin releasing factor 2 receptor. Mol Cell Endocrinol 2006; 251:103-11. [PMID: 16647196 DOI: 10.1016/j.mce.2006.03.040] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 03/28/2006] [Accepted: 03/28/2006] [Indexed: 01/30/2023]
Abstract
Both unacylated ghrelin (UAG) and acylated ghrelin (AG) exert metabolic effects. To investigate the interactions between AG and UAG on ghrelin receptors we evaluated the effects of AG and UAG on INS-1E rat insulinoma cells, using insulin secretion after 30min static incubation as a read-out. A possible involvement of the growth hormone secretagogue receptor type 1a (GHS-R1a) or the corticotropin-releasing factor 2 (CRF2) receptor (CRF2R), as a putative receptor for UAG, was also studied determining their mRNA expression and the functional effects of receptor antagonists on insulin release. Both UAG and AG stimulated insulin release dose-dependently in the nanomolar range. The AG-induced insulin output was antagonized by two GHS-R1a antagonists ([d-Lys(3)]GHRP-6 and BIM28163), which did not block UAG actions. These effects occurred in the presence of low levels of GHS-R1a mRNA. Neither CRF2R expression nor effects of the CRF2R antagonist (astressin(2)B) on insulin output were observed. In conclusion, we provide a sensitive and reproducible assay for specific effects of UAG, which in this study is responsible for insulin release by INS-1E cells. Our data support the existence of a specific receptor for UAG, other than the CRF2R and GHS-R1a. The stimulatory effect on insulin secretion by AG in this cell line is mediated by the GHS-R1a.
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Affiliation(s)
- Carlotta Gauna
- Division of Endocrinology, Department of Internal Medicine, Erasmus MC, Dr Molewaterplein 50, 3015 GE, Rotterdam, The Netherlands.
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Delhanty PJD, van der Eerden BCJ, van der Velde M, Gauna C, Pols HAP, Jahr H, Chiba H, van der Lely AJ, van Leeuwen JPTM. Ghrelin and unacylated ghrelin stimulate human osteoblast growth via mitogen-activated protein kinase (MAPK)/phosphoinositide 3-kinase (PI3K) pathways in the absence of GHS-R1a. J Endocrinol 2006; 188:37-47. [PMID: 16394173 DOI: 10.1677/joe.1.06404] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recent studies demonstrate widespread expression of ghrelin among tissues and have uncovered its pleiotropic nature. We have examined gene expression of ghrelin and its two receptor splice variants, growth hormone secretagogue receptors (GHS-R) 1a and 1b, in human bone biopsies and in the human pre-osteoblastic SV-HFO cell line during differentiation. Additionally, we examined proliferative effects of ghrelin and unacylated ghrelin (UAG) in differentiating and non-differentiating cells. We detected GHS-R1b mRNA in human bone and osteoblasts but not ghrelin's cognate receptor GHS-R1a, using two different real-time PCR assays and both total RNA and mRNA. In osteoblasts GHS-R1b mRNA expression remained low during the first 14 days of culture, but increased 300% in differentiating cells by day 21. Both human bone biopsies and osteoblasts expressed ghrelin mRNA, and osteoblasts were found to secrete ghrelin. Overall, ghrelin gene expression was greater in differentiating than non-differentiating osteoblasts, but was not increased during culture in either group. Ghrelin and UAG induced thymidine uptake dose-dependently, peaking at 1 and 10 nM respectively, at day 6 of culture in both non-differentiating and differentiating osteoblasts. The proliferative response to ghrelin and UAG declined with culture time and state of differentiation. The proliferative effects of ghrelin and UAG were suppressed by inhibitors of extracellular-signal-regulated kinase (ERK) and phosphoinositide-3 kinase, and both peptides rapidly induced ERK phosphorylation. Overall, our data suggest new roles for ghrelin and UAG in modulating human osteoblast proliferation via a novel signal transduction pathway.
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Affiliation(s)
- P J D Delhanty
- Department of Internal Medicine, Erasmus Medical Centre, Dr Molewaterplein 50, 3015 GD Rotterdam, The Netherlands
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Gauna C, Delhanty PJD, Hofland LJ, Janssen JAMJL, Broglio F, Ross RJM, Ghigo E, van der Lely AJ. Ghrelin stimulates, whereas des-octanoyl ghrelin inhibits, glucose output by primary hepatocytes. J Clin Endocrinol Metab 2005; 90:1055-60. [PMID: 15536157 DOI: 10.1210/jc.2004-1069] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Ghrelin exerts various metabolic activities, including regulation of glucose levels in humans. To verify whether the glucose response to ghrelin reflects a modulation of an insulin-independent hepatic phenomenon, we studied glucose output by primary porcine hepatocytes in suspension culture, after incubation with acylated ghrelin (AG), unacylated ghrelin (UAG), and hexarelin (HEX). AG induced glucose output dose dependently after 20 min of incubation (P < 0.001), whereas HEX, a GH secretagogue receptor type 1a (GHS-R1a) agonist, had no effect. UAG inhibited glucose release also dose dependently and after 20 min (P < 0.001). Moreover, UAG completely reversed AG-induced glucose output (P < 0.01). Using real-time PCR, GHS-R1a gene expression was undetectable in all the hepatocyte preparations studied. The lack of efficacy of HEX, the efficacy of UAG, and the absence of GHS-R1a expression indicate the involvement of a yet uncharacterized ghrelin receptor type. In conclusion, glucose output by primary hepatocytes is time- and dose-dependently stimulated by AG and inhibited by UAG. Moreover, UAG counteracts the stimulatory effect of AG on glucose release. These actions might be mediated by a different receptor than GHS-R1a, and apparently, we must consider AG and UAG as separate hormones that can modify each other's actions on glucose handling, at least in the liver.
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Affiliation(s)
- Carlotta Gauna
- Department of Internal Medicine, Section of Endocrinology, Erasmus MC, 3015 GE Rotterdam, The Netherlands.
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Mesotten D, Van den Berghe G, Liddle C, Coulter S, McDougall F, Baxter RC, Delhanty PJD. Growth hormone modulation of the rat hepatic bile transporter system in endotoxin-induced cholestasis. Endocrinology 2003; 144:4008-17. [PMID: 12933675 DOI: 10.1210/en.2003-0139] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Treatment with high dose human GH, although an effective anabolic agent, has been associated with increased incidence of sepsis, inflammation, multiple organ failure, and death in critically ill patients. We hypothesized that GH might increase mortality by exacerbating cholestasis through modulation of bile acid transporter expression. High dose GH was continuously infused over 4 d into rats, and on the final day lipopolysaccharides were injected. Hepatic bile acid transporter expression was measured by Northern analysis and immunoblotting and compared with serum markers of cholestasis and endotoxinemia. Compared with non-GH-treated controls, GH increased endotoxin-induced markers of cholestasis and liver damage as well as augmented IL-6 induction. In endotoxinemia, GH treatment significantly induced multidrug resistance-associated protein 1 mRNA and protein and suppressed organic anion transporting polypeptides, Oatp1 and Oatp4, mRNA, suggesting impaired uptake of bilirubin and bile acids at the basolateral surface of the hepatocyte, which could contribute to the observed worsening of cholestasis by GH. This study of endotoxinemia may thus provide a mechanistic link between GH treatment and exacerbation of cholestasis through modulation of basolateral bile acid transporter expression in the rat hepatocyte.
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Affiliation(s)
- Dieter Mesotten
- Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia.
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Gunton JE, Delhanty PJD, Takahashi SI, Baxter RC. Metformin rapidly increases insulin receptor activation in human liver and signals preferentially through insulin-receptor substrate-2. J Clin Endocrinol Metab 2003; 88:1323-32. [PMID: 12629126 DOI: 10.1210/jc.2002-021394] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Metformin decreases endogenous glucose production by the liver. Few studies have examined the effect of metformin on the insulin-signaling pathway in liver models, and none have presented data on the effect in normal human liver. Huh7 human hepatoma cells and primary human hepatocytes were used. Insulin receptor (IR) and IR substrates (IRS)-1 and -2 were assessed by immunoprecipitation and immunoblot. Normal human liver was used to assay IR kinase activity (IR-KA). Tyrphostin AG1024 was used to inhibit IR-KA and examine effects on deoxyglucose uptake. Metformin (1 micro g/ml) increased IR tyrosine phosphorylation by 78% (P = 0.0007) in 30 min in human hepatocytes and Huh7 cells and increased IRS-2 but not IRS-1 activation, and the downstream increase in deoxyglucose uptake was mediated via increased translocation of GLUT-1 to the plasma membrane. Metformin did not augment maximal or submaximal insulin-stimulated IR activation. Metformin increased basal IR-KA by 150% (P = 0.0001). AG1024 inhibited metformin-induced IR-beta phosphorylation in a concentration-dependent manner and abolished metformin-induced 2-deoxyglucose uptake. This study demonstrates that the mechanism of action of metformin in liver involves IR activation, followed by selective IRS-2 activation, and increased glucose uptake via increased GLUT-1 translocation. The effect of metformin was completely blocked by an IR inhibitor.
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Affiliation(s)
- Jenny E Gunton
- Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, Sydney, New South Wales 2065 Australia.
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Abstract
The GH-dependent, hepatocyte-derived acid-labile subunit (ALS) regulates IGF release from the serum by forming ternary complexes containing IGF binding protein (IGFBP)-3 or IGFBP-5. Malnutrition suppresses ALS and IGF-I expression in a development-dependent manner. Our aim was to investigate whether the effect of feeding following fasting was similarly age dependent. We fasted juvenile and adult rats for 48 h and then refed them, collecting serum and liver tissue at 8, 24, and 48 h. These were compared with rats before fasting (0 h controls) and animals fed throughout the study (free-fed controls). During fasting, serum ALS fell to 25 +/- 5.3% of 0 h controls in juveniles but only 56 +/- 6% in adults. Within 24 h of refeeding, ALS in juveniles had returned to 0 h control levels, and by 48 h to free-fed levels, whereas there was no significant refeeding response in adults during this period. Circulating IGF-I and IGFBP-5 showed similar age-dependent responses to refeeding, rising significantly faster in juveniles. IGFBP-3 did not show this response. Furthermore, hepatic ALS and IGF-I mRNA showed no age-differential response to fasting and refeeding, suggesting posttranscriptional regulation. Neither regulation of hepatic GH receptor nor ALS clearance rates could explain the age-dependent effect. We hypothesize that development-dependent regulation of ALS and IGF-I during refeeding may involve a posttranscriptional hepatic response that is not GH dependent.
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Affiliation(s)
- Sung-Eun Kong
- Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia
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Mesotten D, Delhanty PJD, Vanderhoydonc F, Hardman KV, Weekers F, Baxter RC, Van Den Berghe G. Regulation of insulin-like growth factor binding protein-1 during protracted critical illness. J Clin Endocrinol Metab 2002; 87:5516-23. [PMID: 12466347 DOI: 10.1210/jc.2002-020664] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IGF binding protein-1 (IGFBP-1), an important regulator of IGF bioavailability, has been shown to correlate with mortality in critically ill patients. In the liver, IGFBP-1 is transcriptionally repressed by insulin, and it is therefore a potential marker of hepatic insulin sensitivity. We have recently shown that, compared with conventional treatment, maintenance of normoglycemia with intensive insulin therapy decreased morbidity and mortality of continuously fed critically ill patients. This study compares the effect of conventional and intensive insulin therapy on IGFBP-1 and assesses its predictive value for mortality. In 363 patients who were dependent on intensive care for more than 7 d and were randomly assigned to either conventional or intensive insulin therapy, serum IGFBP-1 levels were measured on admission, on d 1, 8, 15, 22, and 29, and on the day of intensive care unit discharge or death. In addition, IGFBP-1 and phosphoenolpyruvate carboxykinase mRNA levels were measured by real-time RT-PCR in postmortem liver biopsies obtained from 74 patients who died in the intensive care unit. Although intensive insulin treatment lowered glycemia, it had no effect on IGFBP-1 serum levels. Instead, serum IGFBP-1 concentration was significantly higher in patients who ultimately died, and it differentiated nonsurvivors from survivors 3 wk before death. The predictive value of serum IGFBP-1 for mortality was similar to that of the APACHE-II score. Like circulating IGFBP-1, hepatic mRNA levels of IGFBP-1 and the similarly insulin-regulated gene, phosphoenolpyruvate carboxykinase, were not significantly different between conventional and intensive insulin therapy groups. These data suggest that hepatic insulin resistance in prolonged critically ill patients, reflected by high serum IGFBP-1 levels, is not overcome by intensive insulin therapy, and that this may affect patient outcome.
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Affiliation(s)
- Dieter Mesotten
- Department of Intensive Care Medicine, University Hospital Gasthuisberg, Catholic University Leuven, B-3000 Leuven, Belgium
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Abstract
The effect of sustained endotoxemia on expression of the acid-labile subunit (ALS) in relation to hepatic markers of altered GH and insulin sensitivity was examined. Juvenile rats were injected with endotoxin twice daily for 48 h, causing reduced food intake and attenuated growth. In pair-fed controls, food restriction caused marked suppression of ALS gene expression and circulating levels within 12 h, and endotoxemia augmented this effect. This acute effect of endotoxin corresponded temporally with transient induction of suppressor of cytokine signaling (SOCS)-3, cytokine-inducible SH2-containing protein (CIS), phosphoenolpyruvate carboxykinase (PEPCK), and insulin-like growth factor-binding protein (IGFBP)-1 and suppression of GH receptor (GHR). During the subsequent 36 h of sustained endotoxin treatment, expression of ALS recovered to, and then rose above, that of their pair-fed controls. This effect was paralleled by other ternary complex components. The inductive effect of sustained endotoxemia relative to pair-fed controls could not be explained by differences in expression of GHR, SOCS-3, or CIS but coincided with normalized PEPCK and IGFBP-1 levels, suggesting better hepatic insulin sensitivity in these animals. These data may indicate that, in sustained endotoxemia, ALS levels are regulated through modulation of hepatic insulin sensitivity.
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Affiliation(s)
- Sung-Eun Kong
- Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St Leonards, New South Wales 2065, Australia
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