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Abstract
Since the discovery of functionally competent, energy-consuming brown adipose tissue (BAT) in adult humans, much effort has been devoted to exploring this tissue as a means for increasing energy expenditure to counteract obesity. However, despite promising effects on metabolic rate and insulin sensitivity, no convincing evidence for weight-loss effects of cold-activated human BAT exists to date. Indeed, increasing energy expenditure would naturally induce compensatory feedback mechanisms to defend body weight. Interestingly, BAT is regulated by multiple interactions with the hypothalamus from regions overlapping with centers for feeding behavior and metabolic control. Therefore, in the further exploration of BAT as a potential source of novel drug targets, we discuss the hypothalamic orchestration of BAT activity and the relatively unexplored BAT feedback mechanisms on neuronal regulation. With a holistic view on hypothalamic-BAT interactions, we aim to raise ideas and provide a new perspective on this circuit and highlight its clinical relevance.
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Affiliation(s)
- Jo B Henningsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark;
| | - Camilla Scheele
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark;
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Messina A, De Fusco C, Monda V, Esposito M, Moscatelli F, Valenzano A, Carotenuto M, Viggiano E, Chieffi S, De Luca V, Cibelli G, Monda M, Messina G. Role of the Orexin System on the Hypothalamus-Pituitary-Thyroid Axis. Front Neural Circuits 2016; 10:66. [PMID: 27610076 PMCID: PMC4997012 DOI: 10.3389/fncir.2016.00066] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 08/08/2016] [Indexed: 12/25/2022] Open
Abstract
Hypocretin/orexin (ORX) are two hypothalamic neuropeptides discovered in 1998. Since their discovery, they have been one of the most studied neuropeptide systems because of their projecting fields innervating various brain areas. The orexinergic system is tied to sleep-wakefulness cycle, and narcolepsy is a consequence of their system hypofunction. Orexinergic system is also involved in many other autonomic functions such as feeding, thermoregulation, cardiovascular and neuroendocrine regulation. The main aim of this mini review article is to investigate the relationship between ORX and thyroid system regulation. Although knowledge about the ORX system is evolving, its putative effects on hypothalamic-pituitary-thyroid (HPT) axis still appear unclear. We analyzed some studies about ORX control of HPT axis to know better the relationship between them. The studies that were analyzed suggest Hypocretin/ORX to modulate the thyroid regulation, but the nature (excitatory or inhibitory) of this possible interaction remains actually unclear and needs to be confirmed.
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Affiliation(s)
- Antonietta Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Carolina De Fusco
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Maria Esposito
- Neapolitan Brain Group (NBG), Clinic of Child and Adolescent Neuropsychiatry, Department of Mental, Physical Health and Preventive Medicine, Second University of Naples Naples, Italy
| | - Fiorenzo Moscatelli
- Department of Clinical and Experimental Medicine, University of Foggia Foggia, Italy
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia Foggia, Italy
| | - Marco Carotenuto
- Neapolitan Brain Group (NBG), Clinic of Child and Adolescent Neuropsychiatry, Department of Mental, Physical Health and Preventive Medicine, Second University of Naples Naples, Italy
| | - Emanuela Viggiano
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Sergio Chieffi
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Vincenzo De Luca
- Department of Psychiatry, University of Toronto Toronto, ON, Canada
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia Foggia, Italy
| | - Marcellino Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of Naples Naples, Italy
| | - Giovanni Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, Second University of NaplesNaples, Italy; Department of Clinical and Experimental Medicine, University of FoggiaFoggia, Italy
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Brown adipose tissue: a potential target in the fight against obesity and the metabolic syndrome. Clin Sci (Lond) 2015; 129:933-49. [DOI: 10.1042/cs20150339] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BAT (brown adipose tissue) is the main site of thermogenesis in mammals. It is essential to ensure thermoregulation in newborns. It is also found in (some) adult humans. Its capacity to oxidize fatty acids and glucose without ATP production contributes to energy expenditure and glucose homoeostasis. Brown fat activation has thus emerged as an attractive therapeutic target for the treatment of obesity and the metabolic syndrome. In the present review, we integrate the recent advances on the metabolic role of BAT and its relation with other tissues as well as its potential contribution to fighting obesity and the metabolic syndrome.
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Lettieri Barbato D, Tatulli G, Maria Cannata S, Bernardini S, Aquilano K, Ciriolo MR. Glutathione Decrement Drives Thermogenic Program In Adipose Cells. Sci Rep 2015; 5:13091. [PMID: 26260892 PMCID: PMC4531326 DOI: 10.1038/srep13091] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 07/17/2015] [Indexed: 01/21/2023] Open
Abstract
Adipose tissue metabolically adapts to external stimuli. We demonstrate that the induction of the thermogenic program in white adipocytes, through cold exposure in mice or in vitro adrenergic stimulation, is accompanied by a decrease in the intracellular content of glutathione (GSH). Moreover, the treatment with a GSH depleting agent, buthionine sulfoximine (BSO), recapitulates the effect of cold exposure resulting in the induction of thermogenic program. In particular, BSO treatment leads to enhanced uncoupling respiration as demonstrated by increased expression of thermogenic genes (e.g. Ucp1, Ppargc1a), augmented oxygen consumption and decreased mitochondrial transmembrane potential. Buffering GSH decrement by pre-treatment with GSH ester prevents the up-regulation of typical markers of uncoupling respiration. We demonstrate that FoxO1 activation is responsible for the conversion of white adipocytes into a brown phenotype as the “browning” effects of BSO are completely abrogated in cells down-regulating FoxO1. In mice, the BSO-mediated up-regulation of uncoupling genes results in weight loss that is at least in part ascribed to adipose tissue mass reduction. The induction of thermogenic program has been largely proposed to counteract obesity-related diseases. Based on these findings, we propose GSH as a novel therapeutic target to increase energy expenditure in adipocytes.
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Affiliation(s)
- Daniele Lettieri Barbato
- Dept. Biology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Giuseppe Tatulli
- Scientific Institute for Research Hospitalization and Health Care and Università Telematica San Raffaele Roma, Via di Val Cannuta 247, 00166 Rome, Italy
| | - Stefano Maria Cannata
- Dept. Biology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Sergio Bernardini
- Dept. Biology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Katia Aquilano
- 1] Dept. Biology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy [2] Scientific Institute for Research Hospitalization and Health Care and Università Telematica San Raffaele Roma, Via di Val Cannuta 247, 00166 Rome, Italy
| | - Maria R Ciriolo
- 1] Dept. Biology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy [2] Scientific Institute for Research Hospitalization and Health Care and Università Telematica San Raffaele Roma, Via di Val Cannuta 247, 00166 Rome, Italy
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Tohma Y, Akturk M, Altinova A, Yassibas E, Cerit ET, Gulbahar O, Arslan M, Sanlier N, Toruner F. Circulating Levels of Orexin-A, Nesfatin-1, Agouti-Related Peptide, and Neuropeptide Y in Patients with Hyperthyroidism. Thyroid 2015; 25:776-83. [PMID: 25915725 DOI: 10.1089/thy.2014.0515] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND There is insufficient information about the appetite-related hormones orexin-A, nesfatin-1, agouti-related peptide (AgRP), and neuropeptide Y (NPY) in hyperthyroidism. The aim of the present study was to investigate the effects of hyperthyroidism on the basal metabolic rate (BMR) and energy intake, orexin-A, nesfatin-1, AgRP, NPY, and leptin levels in the circulation, and their relationship with each other and on appetite. METHODS In this prospective study, patients were evaluated in hyperthyroid and euthyroid states in comparison with healthy subjects. Twenty-one patients with overt hyperthyroidism and 33 healthy controls were included in the study. RESULTS Daily energy intake in the hyperthyroid state was found to be higher than that in the euthyroid state patient group (p=0.039). BMR was higher in hyperthyroid patients than the control group (p=0.018). Orexin-A was lower and nesfatin-1 was higher in hyperthyroid patients compared to the controls (p<0.001), whereas orexin-A increased and nesfatin-1 decreased after euthyroidism (p=0.003, p<0.001). No differences were found in the AgRP, NPY, and leptin levels between the hyperthyroid and euthyroid states and controls (p>0.05). Orexin-A correlated negatively with nesfatin-1 (p=0.042), BMR (p=0.013), free triiodothyronine (fT3; p<0.001), and free thyroxine (fT4; p<0.001) and positively with thyrotropin (TSH; p<0.001). Nesfatin-1 correlated negatively with orexin-A (p=0.042) and TSH (p<0.001) and positively with fT3 (p=0.005) and fT4 (p=0.001). In the regression analysis, "diagnosis of hyperthyroidism" was the main factor affecting orexin-A (p<0.001). CONCLUSIONS Although it seems that no relationship exists among orexin-A, nesfatin-1, and increased appetite in hyperthyroidism, the orexin-A and nesfatin-1 levels are markedly affected by hyperthyroidism.
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Affiliation(s)
- Yusuf Tohma
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
| | - Mujde Akturk
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
| | - Alev Altinova
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
| | - Emine Yassibas
- 2 Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey
| | - Ethem Turgay Cerit
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
| | - Ozlem Gulbahar
- 3 Department of Biochemistry, Faculty of Medicine, Gazi University , Ankara, Turkey
| | - Metin Arslan
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
| | - Nevin Sanlier
- 2 Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey
| | - Fusun Toruner
- 1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey
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Horne JA. Human REM sleep: influence on feeding behaviour, with clinical implications. Sleep Med 2015; 16:910-6. [PMID: 26122167 DOI: 10.1016/j.sleep.2015.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/12/2015] [Accepted: 04/09/2015] [Indexed: 11/18/2022]
Abstract
Rapid eye movement (REM) sleep shares many underlying mechanisms with wakefulness, to a much greater extent than does non-REM, especially those relating to feeding behaviours, appetite, curiosity, exploratory (locomotor) activities, as well as aspects of emotions, particularly 'fear extinction'. REM is most evident in infancy, thereafter declining in what seems to be a dispensable manner that largely reciprocates increasing wakefulness. However, human adults retain more REM than do other mammals, where for us it is most abundant during our usual final REM period (fREMP) of the night, nearing wakefulness. The case is made that our REM is unusual, and that (i) fREMP retains this 'dispensability', acting as a proxy for wakefulness, able to be forfeited (without REM rebound) and substituted by physical activity (locomotion) when pressures of wakefulness increase; (ii) REM's atonia (inhibited motor output) may be a proxy for this locomotion; (iii) our nocturnal sleep typically develops into a physiological fast, especially during fREMP, which is also an appetite suppressant; (iv) REM may have 'anti-obesity' properties, and that the loss of fREMP may well enhance appetite and contribute to weight gain ('overeating') in habitually short sleepers; (v) as we also select foods for their hedonic (emotional) values, REM may be integral to developing food preferences and dislikes; and (vii) REM seems to have wider influences in regulating energy balance in terms of exercise 'substitution' and energy (body heat) retention. Avenues for further research are proposed, linking REM with feeding behaviours, including eating disorders, and effects of REM-suppressant medications.
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Affiliation(s)
- James A Horne
- Sleep Research Centre, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
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