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Ramasamy I. Physiological Appetite Regulation and Bariatric Surgery. J Clin Med 2024; 13:1347. [PMID: 38546831 PMCID: PMC10932430 DOI: 10.3390/jcm13051347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 04/10/2024] Open
Abstract
Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.
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Affiliation(s)
- Indra Ramasamy
- Department of Blood Sciences, Conquest Hospital, Hastings TN37 7RD, UK
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Lee J, Raycraft L, Johnson AW. The dynamic regulation of appetitive behavior through lateral hypothalamic orexin and melanin concentrating hormone expressing cells. Physiol Behav 2020; 229:113234. [PMID: 33130035 DOI: 10.1016/j.physbeh.2020.113234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The lateral hypothalamic area (LHA) is a heterogeneous brain structure extensively studied for its potent role in regulating energy balance. The anatomical and molecular diversity of the LHA permits the orchestration of responses to energy sensing cues from the brain and periphery. Two of the primary cell populations within the LHA associated with integration of this information are Orexin (ORX) and Melanin Concentrating Hormone (MCH). While both of these non-overlapping populations exhibit orexigenic properties, the activities of these two systems support feeding behavior through contrasting mechanisms. We describe the anatomical and functional properties as well as interaction with other neuropeptides and brain reward and hedonic systems. Specific outputs relating to arousal, food seeking, feeding, and metabolism are coordinated through these mechanisms. We then discuss how both the ORX and MCH systems harmonize in a divergent yet overall cooperative manner to orchestrate feeding behavior through transitions between various appetitive states, and thus offer novel insights into LHA allostatic control of appetite.
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Affiliation(s)
| | | | - Alexander W Johnson
- Department of Psychology; Neuroscience Program, Michigan State University, East Lansing.
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Liu L, Wang Q, Liu A, Lan X, Huang Y, Zhao Z, Jie H, Chen J, Zhao Y. Physiological Implications of Orexins/Hypocretins on Energy Metabolism and Adipose Tissue Development. ACS OMEGA 2020; 5:547-555. [PMID: 31956801 PMCID: PMC6964296 DOI: 10.1021/acsomega.9b03106] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 11/27/2019] [Indexed: 05/09/2023]
Abstract
Orexins/hypocretins and their receptors (OXRs) are ubiquitously distributed throughout the nervous system and peripheral tissues. Recently, various reports have indicated that orexins play regulatory roles in numerous physiological processes involved in obesity, energy homeostasis, sleep-wake cycle, analgesia, alcoholism, learning, and memory. This review aims to outline recent progress in the research and development of orexins used in biochemical signaling pathways, secretion pathways, and the regulation of energy metabolism/adipose tissue development. Orexins regulate a variety of physiological functions in the body by activating phospholipase C/protein kinase C and AC/cAMP/PKA pathways, through receptors coupled to Gq and Gi/Gs, respectively. The secretion of orexins is modulated by blood glucose, blood lipids, hormones, and neuropeptides. Orexins have critical functions in energy metabolism, regulating both feeding behavior and energy expenditure. Increasing the sensitivity of orexin-coupled hypothalamic neurons concurrently enhances spontaneous physical activity, non-exercise activity thermogenesis, white adipose tissue lipolysis, and brown adipose tissue thermogenesis. With this comprehensive review of the current literature on the subject, we hope to provide an integrated perspective for the prevention/treatment of obesity.
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Affiliation(s)
- Lingbin Liu
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
- E-mail: (L.L.)
| | - Qigui Wang
- ChongQing Academy
of Animal Sciences, Rongchang, 402460 Chongqing, P. R. China
| | - Anfang Liu
- College of Animal Science, Southwest University, Rongchang Campus, Rongchang, 402460 Chongqing, P.R. China
| | - Xi Lan
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
| | - Yongfu Huang
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
| | - Zhongquan Zhao
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
| | - Hang Jie
- Chongqing Institute of Medicinal Plant
Cultivation, Nanchuan, 408435 Chongqing, P.R. China
| | - Juncai Chen
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
| | - Yongju Zhao
- College of Animal
Science and Technology, Chongqing Key Laboratory of Forage & Herbivore,
Chongqing Engineering Research Center for Herbivores Resource Protection
and Utilization, Southwest University, Beibei, 400715 Chongqing, P. R. China
- E-mail: (Y.Z.)
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Perry RJ, Resch JM, Douglass AM, Madara JC, Rabin-Court A, Kucukdereli H, Wu C, Song JD, Lowell BB, Shulman GI. Leptin's hunger-suppressing effects are mediated by the hypothalamic-pituitary-adrenocortical axis in rodents. Proc Natl Acad Sci U S A 2019; 116:13670-13679. [PMID: 31213533 PMCID: PMC6613139 DOI: 10.1073/pnas.1901795116] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Leptin informs the brain about sufficiency of fuel stores. When insufficient, leptin levels fall, triggering compensatory increases in appetite. Falling leptin is first sensed by hypothalamic neurons, which then initiate adaptive responses. With regard to hunger, it is thought that leptin-sensing neurons work entirely via circuits within the central nervous system (CNS). Very unexpectedly, however, we now show this is not the case. Instead, stimulation of hunger requires an intervening endocrine step, namely activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Increased corticosterone then activates AgRP neurons to fully increase hunger. Importantly, this is true for 2 forms of low leptin-induced hunger, fasting and poorly controlled type 1 diabetes. Hypoglycemia, which also stimulates hunger by activating CNS neurons, albeit independently of leptin, similarly recruits and requires this pathway by which HPA axis activity stimulates AgRP neurons. Thus, HPA axis regulation of AgRP neurons is a previously underappreciated step in homeostatic regulation of hunger.
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Affiliation(s)
- Rachel J Perry
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Jon M Resch
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Amelia M Douglass
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Joseph C Madara
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Aviva Rabin-Court
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Hakan Kucukdereli
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Chen Wu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Joongyu D Song
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215;
- Program in Neuroscience, Harvard Medical School, Boston, MA 02215
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520;
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
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Abstract
PURPOSE OF REVIEW The hormone cholecystokinin was discovered in 1928 because of its ability to induce gallbladder contraction. Since then, cholecystokinin has been shown to possess multiple functions in the gastrointestinal tract and brain. This review discusses several significant developments in cholecystokinin biology that show how it plays a role in gastrointestinal diseases, including control of appetite. RECENT FINDINGS Cholecystokinin was shown to induce satiety by interacting through CCK-1 receptors located in specialized regions of the hindbrain. Cholecystokinin also inhibits expression of orexigenic peptides in the hypothalamus and prevents stimulation of specialized neurons by ghrelin. In the pancreas, cholecystokinin increased the proliferation of insulin-producing beta cells and reduced insulin-induced hyperphagia. Elevated cholecystokinin levels decreased appetite and reduced intestinal inflammation caused by parasites and bacterial toxins. SUMMARY Understanding the mechanisms by which cholecystokinin regulates orexigenic pathways in the body may lead to strategies for controlling appetite-related disorders such as obesity and bulimia. The reduction of intestinal inflammation by dietary fats (by elevating cholecystokinin) suggests that the hormone plays an integrated role in regulating the ingestion and digestion of food that may be relevant to inflammatory diseases of the gastrointestinal tract.
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Affiliation(s)
- Rashmi Chandra
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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Bibliography. Current world literature. Growth and development. Curr Opin Endocrinol Diabetes Obes 2007; 14:74-89. [PMID: 17940424 DOI: 10.1097/med.0b013e32802e6d87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Arsenijevic D, de Bilbao F, Plamondon J, Paradis E, Vallet P, Richard D, Langhans W, Giannakopoulos P. Increased infarct size and lack of hyperphagic response after focal cerebral ischemia in peroxisome proliferator-activated receptor beta-deficient mice. J Cereb Blood Flow Metab 2006; 26:433-45. [PMID: 16094319 DOI: 10.1038/sj.jcbfm.9600200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are involved in energy expenditure, regulation of inflammatory processes, and cellular protection in peripheral tissues. Among the different types of PPARs, PPARbeta is the only one to be widely expressed in cortical neurons. Using PPARbeta knockout (KO) mice, we report here a detailed investigation of the role of PPARbeta in cerebral ischemic damage, associated inflammatory and antioxidant processes as well as food intake regulation after middle cerebral artery occlusion (MCAO). The PPARbeta KO mice had a two-fold increase in infarct size compared with wild-type (WT) mice. Brain oxidative stress was dramatically enhanced in these KO mice, as documented by an increased content of malondialdehyde, decreased levels of glutathione and manganese superoxide dismutase, and no induction of uncoupling protein 2 (UCP2) mRNA. Unlike WT mice, PPARbeta KO mice showed a marked increase of prooxidant interferon-gamma but no induction of nerve growth factor and tumor necrosis factor alpha after MCAO. In WT mice, MCAO resulted in inflammation-specific transient hyperphagia from day 3 to day 5 after ischemia, which was associated with an increase in neuropeptide Y (NPY) mRNA. This hyperphagic phase and NPY mRNA induction were not observed in PPARbeta KO mice. Furthermore, our study also suggests for the first time that UCP2 is involved in MCAO food intake response. These data indicate that PPARbeta plays an important role in integrating and regulating central inflammation, antioxidant mechanisms, and food intake after MCAO, and suggest that the use of PPARbeta agonists may be of interest for the prevention of central ischemic damage.
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Gallmann E, Arsenijevic D, Williams G, Langhans W, Spengler M. Effect of intraperitoneal CCK-8 on food intake and brain orexin-A after 48 h of fasting in the rat. ACTA ACUST UNITED AC 2006; 133:139-46. [PMID: 16271404 DOI: 10.1016/j.regpep.2005.09.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 09/21/2005] [Accepted: 09/28/2005] [Indexed: 11/18/2022]
Abstract
We investigated the interactions of the peripheral satiety peptide cholecystokinin and the brain orexin-A system in the control of food intake. The effect of an intraperitoneal (i.p.) injection of sulfated cholecystokinin octapeptide (in this article called CCK) (5 microg/kg, 4.4 nmol/kg) or of phosphate-buffered saline (PBS, vehicle control) on 48 h fasting-induced feeding and on orexin-A peptide content was analyzed in diverse brain regions innervated by orexin neurons and involved in the control of food intake. Administration of CCK after a 48 h fast reduced fasting-induced hyperphagia (P<0.05). I.p. CCK increased the orexin-A content in the posterior brainstem of 48 h fasted rats by 35% (P<0.05). Fed animals receiving CCK had 48% higher orexin-A levels in the posterior brainstem than fasted rats (P<0.05). In the lateral hypothalamus, fasting decreased orexin-A levels by 50% as compared to fed rats (P<0.05). In the septal nuclei, the combination of fasting and CCK administration reduced orexin-A contents compared to fed PBS and CCK animals by 13% and 17%, respectively (P<0.05). These results suggest a convergence of pathways activated by peripheral CCK and by fasting on the level of orexin-A released in the posterior brainstem and provide evidence for a novel interaction between peripheral satiety signaling and a brain orexigen in the control of food intake.
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Affiliation(s)
- Eva Gallmann
- Physiology and Animal Husbandry, Institute of Animal Sciences Swiss Federal Institute of Technology, Schwerzenbach, Switzerland.
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