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Dumiaty Y, Underwood BM, Phy-Lim J, Chee MJ. Neurocircuitry underlying the actions of glucagon-like peptide 1 and peptide YY 3-36 in the suppression of food, drug-seeking, and anxiogenesis. Neuropeptides 2024; 105:102427. [PMID: 38579490 DOI: 10.1016/j.npep.2024.102427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/07/2024]
Abstract
Obesity is a critical health condition worldwide that increases the risks of comorbid chronic diseases, but it can be managed with weight loss. However, conventional interventions relying on diet and exercise are inadequate for achieving and maintaining weight loss, thus there is significant market interest for pharmaceutical anti-obesity agents. For decades, receptor agonists for the gut peptide glucagon-like peptide 1 (GLP-1) featured prominently in anti-obesity medications by suppressing appetite and food reward to elicit rapid weight loss. As the neurocircuitry underlying food motivation overlaps with that for drugs of abuse, GLP-1 receptor agonism has also been shown to decrease substance use and relapse, thus its therapeutic potential may extend beyond weight management to treat addictions. However, as prolonged use of anti-obesity drugs may increase the risk of mood-related disorders like anxiety and depression, and individuals taking GLP-1-based medication commonly report feeling demotivated, the long-term safety of such drugs is an ongoing concern. Interestingly, current research now focuses on dual agonist approaches that include GLP-1 receptor agonism to enable synergistic effects on weight loss or associated functions. GLP-1 is secreted from the same intestinal cells as the anorectic gut peptide, Peptide YY3-36 (PYY3-36), thus this review assessed the therapeutic potential and underlying neural circuits targeted by PYY3-36 when administered independently or in combination with GLP-1 to curb the appetite for food or drugs of abuse like opiates, alcohol, and nicotine. Additionally, we also reviewed animal and human studies to assess the impact, if any, for GLP-1 and/or PYY3-36 on mood-related behaviors in relation to anxiety and depression. As dual agonists targeting GLP-1 and PYY3-36 may produce synergistic effects, they can be effective at lower doses and offer an alternative approach for therapeutic benefits while mitigating undesirable side effects.
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Affiliation(s)
- Yasmina Dumiaty
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
| | - Brett M Underwood
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
| | - Jenny Phy-Lim
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
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2
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Torres-Rodriguez JM, Wilson TD, Singh S, Torruella-Suárez ML, Chaudhry S, Adke AP, Becker JJ, Neugebauer B, Lin JL, Martinez Gonzalez S, Soler-Cedeño O, Carrasquillo Y. The parabrachial to central amygdala pathway is critical to injury-induced pain sensitization in mice. Neuropsychopharmacology 2024; 49:508-520. [PMID: 37542159 PMCID: PMC10789863 DOI: 10.1038/s41386-023-01673-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/27/2023] [Accepted: 07/12/2023] [Indexed: 08/06/2023]
Abstract
The spino-ponto-amygdaloid pathway is a major ascending circuit relaying nociceptive information from the spinal cord to the brain. Potentiation of excitatory synaptic transmission in the parabrachial nucleus (PBN) to central amygdala (CeA) pathway has been reported in rodent models of persistent pain. However, the functional significance of this pathway in the modulation of the somatosensory component of pain was recently challenged by studies showing that spinal nociceptive neurons do not target CeA-projecting PBN cells and that manipulations of this pathway have no effect on reflexive-defensive somatosensory responses to peripheral noxious stimulation. Here, we showed that activation of CeA-projecting PBN neurons is critical to increase both stimulus-evoked and spontaneous nociceptive responses following an injury in male and female mice. Using optogenetic-assisted circuit mapping, we confirmed a functional excitatory projection from PBN→CeA that is independent of the genetic or firing identity of CeA cells. We then showed that peripheral noxious stimulation increased the expression of the neuronal activity marker Fos in CeA-projecting PBN neurons and that chemogenetic inactivation of these cells decreased behavioral hypersensitivity in models of neuropathic and inflammatory pain without affecting baseline nociception. Lastly, we showed that chemogenetic activation of CeA-projecting PBN neurons is sufficient to induced bilateral hypersensitivity without injury. Together, our results indicate that the PBN→CeA pathway is a key modulator of pain-related behaviors that can increase reflexive-defensive and affective-motivational responses to somatosensory stimulation in injured states without affecting nociception under normal physiological conditions.
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Affiliation(s)
- Jeitzel M Torres-Rodriguez
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Torri D Wilson
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Sudhuman Singh
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Maria L Torruella-Suárez
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Sarah Chaudhry
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Anisha P Adke
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Jordan J Becker
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Benjamin Neugebauer
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Jenny L Lin
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Santiago Martinez Gonzalez
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Omar Soler-Cedeño
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Yarimar Carrasquillo
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA.
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA.
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3
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Alabduljabbar K, Bonanos E, Miras AD, le Roux CW. Mechanisms of Action of Bariatric Surgery on Body Weight Regulation. Gastroenterol Clin North Am 2023; 52:691-705. [PMID: 37919021 DOI: 10.1016/j.gtc.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Bariatric surgery is an effective treatment modality for obesity and obesity-associated complications. Weight loss after bariatric surgery was initially attributed to anatomic restriction or reduced energy absorption, but now it is understood that surgery treats obesity by influencing the subcortical areas of the brain to lower adipose tissue mass. There are three major phases of this process: initially the weight loss phase, followed by a phase where weight loss is maintained, and in a subset of patients a phase where weight is regained. These phases are characterized by altered appetitive behavior together with changes in energy expenditure. The mechanisms associated with the rearrangement of the gastrointestinal tract include central appetite control, release of gut peptides, change in microbiota and bile acids. However, the exact combination and timing of signals remain largely unknown.
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Affiliation(s)
- Khaled Alabduljabbar
- Diabetes Complications Research Centre, Conway Institute, University College Dublin, Dublin, Ireland; Department of Family Medicine and Polyclinics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
| | | | | | - Carel W le Roux
- Diabetes Complications Research Centre, Conway Institute, University College Dublin, Dublin, Ireland.
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4
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Ye J, Hu Y, Wang C, Lian H, Dong Z. Cellular mechanism of diabetes remission by bariatric surgery. Trends Endocrinol Metab 2023; 34:590-600. [PMID: 37574405 DOI: 10.1016/j.tem.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/13/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023]
Abstract
Bariatric surgery is a powerful therapy for type 2 diabetes in patients with obesity. The mechanism of insulin sensitization by surgery has been extensively investigated in weight loss-dependent and weight loss-independent conditions. However, a consensus remains to be established regarding the underlying mechanisms. Energy deficit induced by calorie restriction (CR), that occurs both before and after surgery, represents a unique physiological basis for insulin sensitization regardless of weight loss. In support, we integrate evidence in the literature to provide an energy-based view of insulin sensitization as follows: surgery improves insulin sensitivity through the energy deficit induced by CR, leading to correction of mitochondrial overload in multiple cell types; this then triggers functional reprogramming of relevant tissues leading to diabetes remission.
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Affiliation(s)
- Jianping Ye
- Metabolic Disease Research Center, Zhengzhou University Affiliated Zhengzhou Central Hospital, Zhengzhou 450007, China; Center for Advanced Medicine, College of Medicine, Zhengzhou University, Zhengzhou 450052, China; Research Center for Basic Medicine, Academy of Medical Sciences, Zhengzhou University, Zhengzhou 450052, China.
| | - Yangxi Hu
- Department of Metabolic Surgery, Zhengzhou University Affiliated Zhengzhou Central Hospital, Zhengzhou 450007, China
| | - Chengming Wang
- Metabolic Disease Research Center, Zhengzhou University Affiliated Zhengzhou Central Hospital, Zhengzhou 450007, China
| | - Hongkai Lian
- Trauma Research Center, Zhengzhou University Affiliated Zhengzhou Central Hospital, Zhengzhou 450007, China
| | - Zigang Dong
- Center for Advanced Medicine, College of Medicine, Zhengzhou University, Zhengzhou 450052, China
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5
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Frick LD, Hankir MK, Borner T, Malagola E, File B, Gero D. Novel Insights into the Physiology of Nutrient Sensing and Gut-Brain Communication in Surgical and Experimental Obesity Therapy. Obes Surg 2023; 33:2906-2916. [PMID: 37474864 PMCID: PMC10435392 DOI: 10.1007/s11695-023-06739-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023]
Abstract
Despite standardized surgical technique and peri-operative care, metabolic outcomes of bariatric surgery are not uniform. Adaptive changes in brain function may play a crucial role in achieving optimal postbariatric weight loss. This review follows the anatomic-physiologic structure of the postbariatric nutrient-gut-brain communication chain through its key stations and provides a concise summary of recent findings in bariatric physiology, with a special focus on the composition of the intestinal milieu, intestinal nutrient sensing, vagal nerve-mediated gastrointestinal satiation signals, circulating hormones and nutrients, as well as descending neural signals from the forebrain. The results of interventional studies using brain or vagal nerve stimulation to induce weight loss are also summarized. Ultimately, suggestions are made for future diagnostic and therapeutic research for the treatment of obesity.
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Affiliation(s)
- Lukas D Frick
- Institute of Neuropathology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Tito Borner
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ermanno Malagola
- Division of Digestive and Liver Diseases, Department of Medicine and Irving Cancer Research Center, Columbia University Medical Center, New York, NY, 10032, USA
| | - Bálint File
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Wigner Research Centre for Physics, Budapest, Hungary
| | - Daniel Gero
- Department of Surgery and Transplantation, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zürich, Switzerland.
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6
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Torres-Rodriguez JM, Wilson TD, Singh S, Chaudhry S, Adke AP, Becker JJ, Lin JL, Martinez Gonzalez S, Soler-Cedeño O, Carrasquillo Y. The parabrachial to central amygdala circuit is a key mediator of injury-induced pain sensitization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.08.527340. [PMID: 36945586 PMCID: PMC10028796 DOI: 10.1101/2023.02.08.527340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The spino-ponto-amygdaloid pathway is a major ascending circuit relaying nociceptive information from the spinal cord to the brain. Potentiation of excitatory synaptic transmission in the parabrachial nucleus (PbN) to central amygdala (CeA) pathway has been reported in rodent models of persistent pain. At the behavioral level, the PbN→CeA pathway has been proposed to serve as a general alarm system to potential threats that modulates pain-related escape behaviors, threat memory, aversion, and affective-motivational (but not somatosensory) responses to painful stimuli. Increased sensitivity to previously innocuous somatosensory stimulation is a hallmark of chronic pain. Whether the PbN→CeA circuit contributes to heightened peripheral sensitivity following an injury, however, remains unknown. Here, we demonstrate that activation of CeA-projecting PbN neurons contributes to injury-induced behavioral hypersensitivity but not baseline nociception in male and female mice. Using optogenetic assisted circuit mapping, we confirmed a functional excitatory projection from PbN→CeA that is independent of the genetic or firing identity of CeA cells. We then showed that peripheral noxious stimulation increases the expression of the neuronal activity marker c-Fos in CeA-projecting PbN neurons and chemogenetic inactivation of these cells reduces behavioral hypersensitivity in models of neuropathic and inflammatory pain without affecting baseline nociception. Lastly, we show that chemogenetic activation of CeA-projecting PbN neurons is sufficient to induce bilateral hypersensitivity without injury. Together, our results demonstrate that the PbN→CeA pathway is a key modulator of pain-related behaviors that can amplify responses to somatosensory stimulation in pathological states without affecting nociception under normal physiological conditions. Significance Statement Early studies identified the spino-ponto-amygdaloid pathway as a major ascending circuit conveying nociceptive inputs from the spinal cord to the brain. The functional significance of this circuit to injury-induced hypersensitivity, however, remains unknown. Here, we addressed this gap in knowledge using viral-mediated anatomical tracers, ex-vivo electrophysiology and chemogenetic intersectional approaches in rodent models of persistent pain. We found that activation of this pathway contributes to injury-induced hypersensitivity, directly demonstrating a critical function of the PbN→CeA circuit in pain modulation.
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Affiliation(s)
| | - Torri D. Wilson
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Sudhuman Singh
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Sarah Chaudhry
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Anisha P. Adke
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Jordan J. Becker
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Jenny L. Lin
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | | | - Omar Soler-Cedeño
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Yarimar Carrasquillo
- National Center for Complementary and Integrative Health, Bethesda, MD, United States
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, United States
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7
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Albaugh VL, He Y, Münzberg H, Morrison CD, Yu S, Berthoud HR. Regulation of body weight: Lessons learned from bariatric surgery. Mol Metab 2023; 68:101517. [PMID: 35644477 PMCID: PMC9938317 DOI: 10.1016/j.molmet.2022.101517] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/04/2022] [Accepted: 05/21/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Bariatric or weight loss surgery is currently the most effective treatment for obesity and metabolic disease. Unlike dieting and pharmacology, its beneficial effects are sustained over decades in most patients, and mortality is among the lowest for major surgery. Because there are not nearly enough surgeons to implement bariatric surgery on a global scale, intensive research efforts have begun to identify its mechanisms of action on a molecular level in order to replace surgery with targeted behavioral or pharmacological treatments. To date, however, there is no consensus as to the critical mechanisms involved. SCOPE OF REVIEW The purpose of this non-systematic review is to evaluate the existing evidence for specific molecular and inter-organ signaling pathways that play major roles in bariatric surgery-induced weight loss and metabolic benefits, with a focus on Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), in both humans and rodents. MAJOR CONCLUSIONS Gut-brain communication and its brain targets of food intake control and energy balance regulation are complex and redundant. Although the relatively young science of bariatric surgery has generated a number of hypotheses, no clear and unique mechanism has yet emerged. It seems increasingly likely that the broad physiological and behavioral effects produced by bariatric surgery do not involve a single mechanism, but rather multiple signaling pathways. Besides a need to improve and better validate surgeries in animals, advanced techniques, including inducible, tissue-specific knockout models, and the use of humanized physiological traits will be necessary. State-of-the-art genetically-guided neural identification techniques should be used to more selectively manipulate function-specific pathways.
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Affiliation(s)
- Vance L Albaugh
- Translational and Integrative Gastrointestinal and Endocrine Research Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Yanlin He
- Brain Glycemic and Metabolism Control Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Heike Münzberg
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Christopher D Morrison
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Sangho Yu
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition & Metabolism Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
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Alcantara IC, Tapia APM, Aponte Y, Krashes MJ. Acts of appetite: neural circuits governing the appetitive, consummatory, and terminating phases of feeding. Nat Metab 2022; 4:836-847. [PMID: 35879462 PMCID: PMC10852214 DOI: 10.1038/s42255-022-00611-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/16/2022] [Indexed: 12/11/2022]
Abstract
The overconsumption of highly caloric and palatable foods has caused a surge in obesity rates in the past half century, thereby posing a healthcare challenge due to the array of comorbidities linked to heightened body fat accrual. Developing treatments to manage body weight requires a grasp of the neurobiological basis of appetite. In this Review, we discuss advances in neuroscience that have identified brain regions and neural circuits that coordinate distinct phases of eating: food procurement, food consumption, and meal termination. While pioneering work identified several hypothalamic nuclei to be involved in feeding, more recent studies have explored how neuronal populations beyond the hypothalamus, such as the mesolimbic pathway and nodes in the hindbrain, interconnect to modulate appetite. We also examine how long-term exposure to a calorically dense diet rewires feeding circuits and alters the response of motivational systems to food. Understanding how the nervous system regulates eating behaviour will bolster the development of medical strategies that will help individuals to maintain a healthy body weight.
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Affiliation(s)
- Ivan C Alcantara
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | | | - Yeka Aponte
- National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.
- National Institute on Drug Abuse (NIDA), National Institutes of Health, Baltimore, MD, USA.
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9
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Lutz TA. Creating the amylin story. Appetite 2022; 172:105965. [DOI: 10.1016/j.appet.2022.105965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 02/07/2023]
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10
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Akalestou E, Miras AD, Rutter GA, le Roux CW. Mechanisms of Weight Loss After Obesity Surgery. Endocr Rev 2022; 43:19-34. [PMID: 34363458 PMCID: PMC8755990 DOI: 10.1210/endrev/bnab022] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Indexed: 02/07/2023]
Abstract
Obesity surgery remains the most effective treatment for obesity and its complications. Weight loss was initially attributed to decreased energy absorption from the gut but has since been linked to reduced appetitive behavior and potentially increased energy expenditure. Implicated mechanisms associating rearrangement of the gastrointestinal tract with these metabolic outcomes include central appetite control, release of gut peptides, change in microbiota, and bile acids. However, the exact combination and timing of signals remain largely unknown. In this review, we survey recent research investigating these mechanisms, and seek to provide insights on unanswered questions over how weight loss is achieved following bariatric surgery which may eventually lead to safer, nonsurgical weight-loss interventions or combinations of medications with surgery.
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Affiliation(s)
- Elina Akalestou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Alexander D Miras
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.,Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore.,University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Carel W le Roux
- Diabetes Complications Research Centre, University College Dublin, Ireland.,Diabetes Research Group, School of Biomedical Science, Ulster University, Belfast, UK
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Weight loss from caloric restriction vs Roux-en-Y gastric bypass surgery differentially regulates systemic and portal vein GDF15 levels in obese Zucker fatty rats. Physiol Behav 2021; 240:113534. [PMID: 34303715 DOI: 10.1016/j.physbeh.2021.113534] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 01/05/2023]
Abstract
Weight loss from caloric restriction (i.e. dieting) tends to be modest and short-lived, whereas from bariatric surgeries such as Roux-en-Y gastric bypass (RYGB) is pronounced and generally sustained. The reasons behind these opposing outcomes between interventions remain unclear, but likely involve differential effects on gut-brain communication. Growth differentiation factor 15 (GDF15) is a ubiquitously-induced, centrally-acting, anorexigenic cytokine whose systemic levels are elevated under a variety of conditions associated with a negative energy balance, including in patients following RYGB. We therefore asked whether systemic and portal vein GDF15 levels differ between obese Zucker fatty rats that experienced similar weight loss from RYGB or from forced caloric restriction (CR). Compared with ad libitum fed (ALF) controls, body weight, visceral adiposity and food intake of RYGB and CR rats were markedly lower during the postoperative observation period. Both systemic and portal vein GDF15 levels in RYGB rats at postoperative day 28 were higher compared with ALF rats and particularly compared with CR rats. Further, systemic and portal vein GDF15 levels negatively correlated with body weight and food intake specifically in RYGB rats. These findings provide evidence that, unlike dieting, RYGB might achieve sustained weight loss and appetite suppression partly through increased GDF15 release from epithelial cells of the gastrointestinal tract.
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12
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Gautron L. The Phantom Satiation Hypothesis of Bariatric Surgery. Front Neurosci 2021; 15:626085. [PMID: 33597843 PMCID: PMC7882491 DOI: 10.3389/fnins.2021.626085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/06/2021] [Indexed: 01/26/2023] Open
Abstract
The excitation of vagal mechanoreceptors located in the stomach wall directly contributes to satiation. Thus, a loss of gastric innervation would normally be expected to result in abrogated satiation, hyperphagia, and unwanted weight gain. While Roux-en-Y-gastric bypass (RYGB) inevitably results in gastric denervation, paradoxically, bypassed subjects continue to experience satiation. Inspired by the literature in neurology on phantom limbs, I propose a new hypothesis in which damage to the stomach innervation during RYGB, including its vagal supply, leads to large-scale maladaptive changes in viscerosensory nerves and connected brain circuits. As a result, satiation may continue to arise, sometimes at exaggerated levels, even in subjects with a denervated or truncated stomach. The same maladaptive changes may also contribute to dysautonomia, unexplained pain, and new emotional responses to eating. I further revisit the metabolic benefits of bariatric surgery, with an emphasis on RYGB, in the light of this phantom satiation hypothesis.
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Affiliation(s)
- Laurent Gautron
- Department of Internal Medicine, Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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13
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Foll CL, Lutz TA. Systemic and Central Amylin, Amylin Receptor Signaling, and Their Physiological and Pathophysiological Roles in Metabolism. Compr Physiol 2020; 10:811-837. [PMID: 32941692 DOI: 10.1002/cphy.c190034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article in the Neural and Endocrine Section of Comprehensive Physiology discusses the physiology and pathophysiology of the pancreatic hormone amylin. Shortly after its discovery in 1986, amylin has been shown to reduce food intake as a satiation signal to limit meal size. Amylin also affects food reward, sensitizes the brain to the catabolic actions of leptin, and may also play a prominent role in the development of certain brain areas that are involved in metabolic control. Amylin may act at different sites in the brain in addition to the area postrema (AP) in the caudal hindbrain. In particular, the sensitizing effect of amylin on leptin action may depend on a direct interaction in the hypothalamus. The concept of central pathways mediating amylin action became more complex after the discovery that amylin is also synthesized in certain hypothalamic areas but the interaction between central and peripheral amylin signaling remains currently unexplored. Amylin may also play a dominant pathophysiological role that is associated with the aggregation of monomeric amylin into larger, cytotoxic molecular entities. This aggregation in certain species may contribute to the development of type 2 diabetes mellitus but also cardiovascular disease. Amylin receptor pharmacology is complex because several distinct amylin receptor subtypes have been described, because other neuropeptides [e.g., calcitonin gene-related peptide (CGRP)] can also bind to amylin receptors, and because some components of the functional amylin receptor are also used for other G-protein coupled receptor (GPCR) systems. © 2020 American Physiological Society. Compr Physiol 10:811-837, 2020.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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Abstract
Reviewed here are multiple mouse models of vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) that have emerged over the past decade. These models use diverse approaches to both operative and perioperative procedures. Scrutinizing the benefits and pitfalls of each surgical model and what to expect in terms of post-operative outcomes will enhance our assessment of studies using mouse models, as well as advance our understanding of their translational potential. Two mouse models of bariatric surgery, VSG-lembert and RYGB-small pouch, demonstrate low mortality and most closely recapitulate the human forms of surgery. The use of liquid diets can be minimized, and in mice, RYGB demonstrates more reliable and longer lasting effects on weight loss compared to that of VSG.
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15
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Brehm B, Summer S, Jenkins T, D'Alessio D, Inge T. Thermic effect of food and resting energy expenditure after sleeve gastrectomy for weight loss in adolescent females. Surg Obes Relat Dis 2020; 16:599-606. [PMID: 32146085 DOI: 10.1016/j.soard.2020.01.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 01/20/2020] [Accepted: 01/25/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Few studies have addressed the effect of bariatric surgery on factors related to energy balance, including resting energy expenditure (REE) and thermic effect of food (TEF). To our knowledge, very few studies have examined changes in REE and none have investigated modifications in TEF after sleeve gastrectomy (SG) performed in adolescents. OBJECTIVE To assess energy expenditure in females who underwent SG as adolescents and matched-control participants as preliminary data about the potential of SG to confer differences in postprandial energy expenditure. SETTING Children's Hospital Medical Center, Cincinnati, Ohio, United States. METHODS In this observational study, REE and respiratory quotient (RQ) were measured via indirect calorimetry, followed by a standardized meal and assessment of TEF and postprandial RQ. Plasma drawn before and every 15 minutes after the meal was assayed for insulin, glucose, and C-peptide. Usual dietary intake was estimated using 24-hour recall interviews. RESULTS Fasting REE and RQ were similar between surgical and control groups. Postmeal TEF also did not differ between groups. The surgical group had higher RQ early in the postprandial period, whereas the control group RQ was higher after 125 minutes post meal. Compared with the control group, the surgical group had lower postprandial glucose, higher insulin and C-peptide, and consumed less daily energy during usual intake. CONCLUSIONS Postprandial RQ was consistent with the rapid gastric emptying typical of SG, yet we observed no group differences in REE or TEF. These findings may have been due to limited statistical power. More comprehensive studies of EE after SG are warranted.
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Affiliation(s)
- Bonnie Brehm
- College of Nursing, University of Cincinnati, Cincinnati, Ohio.
| | - Suzanne Summer
- Schubert Research Clinic, Cincinnati Children's Hospital Medical Center Cincinnati, Cincinnati, Ohio
| | - Todd Jenkins
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center Cincinnati, Cincinnati, Ohio
| | - David D'Alessio
- Division of Endocrinology, Department of Medicine, Duke University, Durham, North Carolina
| | - Thomas Inge
- Department of Surgery, University of Colorado Denver School of Medicine and Children's Hospital of Colorado, Aurora, Colorado
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16
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Ma N, Ma R, Tang K, Li X, He B. Roux-en-Y Gastric Bypass in Obese Diabetic Rats Promotes Autophagy to Improve Lipid Metabolism through mTOR/p70S6K Signaling Pathway. J Diabetes Res 2020; 2020:4326549. [PMID: 32309446 PMCID: PMC7136782 DOI: 10.1155/2020/4326549] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/28/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To investigate the effects of Roux-en-Y gastric bypass (RYGB) surgery on markers of liver mitochondrial dynamics and find new therapeutic basis on obese type 2 diabetes mellitus (T2DM) patients. Materials and Methods. Thirty-two rats were divided into nondiabetic group, diabetic group, sham group, and RYGB group. The Dual-energy X-ray absorptiometry (DEXA) was used to detect short-term curriculum vitae for rat body component and fat and lean mass. Hepatic lipid content and triglyceride levels were detected by Oil Red O staining. Western blotting was used to examine autophagy and mammalian target of rapamycin/P70S6 kinase (mTOR/p70S6K) pathway-related proteins. The carbon dioxide production from the oxidation of [14C] oleate was measured. Plasma glucose was measured by glucose oxidase assay. The insulin and C-peptide were detected. Triacylglyceride (TG) and free fat acid (FFA) in plasma were determined by enzymatic colorimetric assays. RESULTS RYGB improved metabolic parameters and enhanced plasma GLP-1 level, ameliorated the lipopexia, and increased insulin sensitivity in the liver; RYGB promoted the hepatic autophagy and inhibited the mTOR/p70S6K signaling pathway. GLP-1 reduced fat load and increased fatty acid β-oxidation by activated autophagy to regulate the hepatic lipid pathway through mTOR/p70S6K signaling pathway. CONCLUSIONS RYGB may reduce liver lipid toxicity and improve insulin sensitivity through activating the hepatic fat hydrolysis pathway and inhibiting the liver fat synthesis pathway. However, the transport pathway of liver fat does not play a key role.
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Affiliation(s)
- Nanxi Ma
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China
| | - Rui Ma
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China
| | - Kaixin Tang
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China
| | - Xuesong Li
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China
| | - Bing He
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China
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Brutman JN, Sirohi S, Davis JF. Recent Advances in the Neurobiology of Altered Motivation Following Bariatric Surgery. Curr Psychiatry Rep 2019; 21:117. [PMID: 31707546 DOI: 10.1007/s11920-019-1084-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW There is compelling evidence in the clinical population that long-term weight loss secondary to bariatric surgery is mitigated by the reemergence of maladaptive feeding behaviors and in some cases new onset substance abuse. RECENT FINDINGS A review of the current literature suggests that physical restructuring of the GI tract during WLS alters secretion of feeding peptides and nutrient-sensing mechanisms that directly target the brain's endogenous reward system, the mesolimbic dopamine system. Post-surgical changes in GI physiology augment activation of the mesolimbic system. In some patients, this process may contribute to a reduced appetite for palatable food whereas in others it may support maladaptive motivated behavior for food and chemical drugs. It is concluded that future studies are required to detail the timing and duration of surgical-induced changes in GI-mesolimbic communication to more fully understand this phenomenon.
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Affiliation(s)
- Julianna N Brutman
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, 1815 Ferdinand's Lane, Pullman, WA, 99164, USA
| | - Sunil Sirohi
- Laboratory of Endocrine and Neuropsychiatric Disorders, Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, USA
| | - Jon F Davis
- Department of Integrative Physiology and Neuroscience, College of Veterinary Medicine, Washington State University, 1815 Ferdinand's Lane, Pullman, WA, 99164, USA.
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18
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Shah H, Shin AC. Meal patterns after bariatric surgery in mice and rats. Appetite 2019; 146:104340. [PMID: 31265857 DOI: 10.1016/j.appet.2019.104340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/19/2019] [Accepted: 06/28/2019] [Indexed: 12/12/2022]
Abstract
With behavioral and pharmacological interventions continuously failing to tackle the obesity epidemic, bariatric surgery has been hailed as the most effective treatment strategy. Current literature suggests that bariatric surgery successfully decreases body weight and excess fat mass through targeting both variables of the energy homeostasis - energy intake and energy expenditure. Here we review current knowledge on changes in caloric consumption, an important arm in the energy balance equation, in rodent models of bariatric surgery. In particular, circadian feeding dynamics, post-surgical caloric intake at both "rapid weight loss" phase and "weight maintenance" phase, as well as meal pattern analysis will be the subject of this review. Considering that different types of bariatric surgery may trigger differential energy intake dynamics resulting in variable weight loss outcomes, the effects of most popular surgeries - vertical sleeve gastrectomy (VSG), Roux-en-Y gastric bypass (RYGB), and gastric banding (GB) - are elaborated. Potential candidate mechanisms underlying alterations in food intake and meal patterns following different bariatric procedures are briefly discussed at the end.
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Affiliation(s)
- Harsh Shah
- Department of Nutritional Sciences, College of Human Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Andrew C Shin
- Department of Nutritional Sciences, College of Human Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
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19
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Kjaergaard M, Salinas CBG, Rehfeld JF, Secher A, Raun K, Wulff BS. PYY(3-36) and exendin-4 reduce food intake and activate neuronal circuits in a synergistic manner in mice. Neuropeptides 2019; 73:89-95. [PMID: 30471778 DOI: 10.1016/j.npep.2018.11.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/17/2018] [Accepted: 11/18/2018] [Indexed: 12/11/2022]
Abstract
Peptide YY(3-36) ((PYY(3-36)) and glucagon like peptide 1 (GLP-1) in combination reduce food intake and body weight in an additive or synergistic manner in animal models and in humans. Nevertheless, the mechanisms behind are not completely understood. The present study aims to investigate the effect of combining PYY(3-36) and the GLP-1 receptor agonist exendin-4 (Ex4) by examining acute food intake and global neuronal activation as measured by c-fos in C57BL/6 J mice. An additive reduction in food intake was found 1.5 h after s.c dosing with the combination of PYY(3-36) (200 μg/kg) and Ex4 (2.5 μg/kg). This was associated with a synergistic enhancement of c-fos reactivity in central amygdalar nucleus (CeA), rostral part of the mediobasal arcuate nucleus (ARH), supratrigeminal nucleus (SUT), lateral parabrachial nucleus (PB), area postrema (AP) and nucleus tractus solitarius (NTS) compared to vehicle, PYY(3-36) and Ex4 individually dosed mice. The regions activated by Ex4 individually and PYY(3-36) and Ex4 in combination resembled each other, but the combination group had a significantly stronger c-fos response. Twenty-five brain areas were activated by PYY(3-36) and Ex4 in combination compared to vehicle versus nine brain areas by Ex4 individually. No significant increase in c-fos reactivity was found by PYY(3-36) compared to vehicle dosed mice. The neuronal activation of ARH and the AP/NTS to PB to CeA pathway is important for appetite regulation while SUT has not previously been reported in the regulation of energy balance. As PYY(3-36) and Ex4 act on different neurons leading to recruitment of different signalling pathways within and to the brain, an interaction of these pathways may contribute to their additive/synergistic action. Thus, PYY(3-36) boosts the effect of Ex4 possibly by inducing less inhibition of neuronal activity leading to an enhanced neuronal activity induced by Ex4.
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Affiliation(s)
- Marina Kjaergaard
- Histology and Imaging, Novo Nordisk A/S, 2760 Måløv, Denmark.; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark..
| | | | - Jens F Rehfeld
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Anna Secher
- Histology and Imaging, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Kirsten Raun
- Obesity Research, Novo Nordisk A/S, 2760 Måløv, Denmark
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20
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Lutz TA. Considering our methods: Methodological issues with rodent models of appetite and obesity research. Physiol Behav 2018; 192:182-187. [DOI: 10.1016/j.physbeh.2018.02.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/10/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022]
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21
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Palmiter RD. The Parabrachial Nucleus: CGRP Neurons Function as a General Alarm. Trends Neurosci 2018; 41:280-293. [PMID: 29703377 PMCID: PMC5929477 DOI: 10.1016/j.tins.2018.03.007] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/17/2018] [Accepted: 03/07/2018] [Indexed: 12/24/2022]
Abstract
The parabrachial nucleus (PBN), which is located in the pons and is dissected by one of the major cerebellar output tracks, is known to relay sensory information (visceral malaise, taste, temperature, pain, itch) to forebrain structures including the thalamus, hypothalamus, and extended amygdala. The availability of mouse lines expressing Cre recombinase selectively in subsets of PBN neurons and viruses for Cre-dependent gene expression is beginning to reveal the connectivity and functions of PBN component neurons. This review focuses on PBN neurons expressing calcitonin gene-related peptide (CGRPPBN) that play a major role in regulating appetite and transmitting real or potential threat signals to the extended amygdala. The functions of other specific PBN neuronal populations are also discussed. This review aims to encourage investigation of the numerous unanswered questions that are becoming accessible.
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Affiliation(s)
- Richard D Palmiter
- Howard Hughes Medical Institute, and Departments of Biochemistry and Genome Sciences, University of Washington, Seattle, WA 98195, USA.
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22
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Hankir MK, Seyfried F, Miras AD, Cowley MA. Brain Feeding Circuits after Roux-en-Y Gastric Bypass. Trends Endocrinol Metab 2018; 29:218-237. [PMID: 29475578 DOI: 10.1016/j.tem.2018.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/17/2018] [Accepted: 01/25/2018] [Indexed: 12/12/2022]
Abstract
Metabolic surgical procedures, such as Roux-en-Y gastric bypass (RYGB), uniquely reprogram feeding behavior and body weight in obese subjects. Clinical neuroimaging and animal studies are only now beginning to shed light on some of the underlying central mechanisms. We present here the roles of key brain neurotransmitter/neuromodulator systems in food choice, value, and intake at various stages after RYGB. In doing so, we elaborate on how known signals emanating from the reorganized gut, including peptide hormones and microbiota products, impinge on newly mapped homeostatic and hedonic brain feeding circuits. Continued progress in the rapidly evolving field of metabolic surgery will inform the design of more effective weight-loss compounds.
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Affiliation(s)
- Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany; German Research Foundation Collaborative Research Center in Obesity Mechanisms, University of Leipzig, Leipzig, Saxony 04103, Germany.
| | - Florian Seyfried
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany
| | - Alexander D Miras
- Department of Investigative Science, Imperial College London Academic Healthcare Centre, London W12 0NN, UK
| | - Michael A Cowley
- Metabolic Disease and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia; Department of Physiology, Monash University, Victoria 3800, Australia
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23
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Stefanidis A, Oldfield BJ. Neuroendocrine mechanisms underlying bariatric surgery: Insights from human studies and animal models. J Neuroendocrinol 2017; 29. [PMID: 28887853 DOI: 10.1111/jne.12534] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 02/06/2023]
Abstract
Obesity has reached epidemic proportions and, to date, bariatric surgery remains the only effective treatment for morbid obesity in terms of its capacity to achieve durable weight loss. Bariatric surgery procedures, including Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB) and sleeve gastrectomy (SG), have been the primary procedures conducted over the past decade, with SG increasing in popularity over the past 5 years at the expense of both RYGB and AGB. Although these procedures were initially proposed to function via restrictive or malabsorptive mechanisms, it is now clear that profound physiological changes underlie the metabolic improvements in patients who undergo bariatric surgery. Data generated in human patients and animal models highlight the rapid and sustained changes in gut hormones that coincide with these procedures. Furthermore, recent studies highlight the involvement of the nervous system, specifically the vagus nerve, in mediating the reduction in appetite and food intake following bariatric surgery. What is unclear is where these pathways converge and interact within the gut-brain axis and whether vagally-mediated circuits are sufficient to drive the metabolic sequalae following bariatric surgery.
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Affiliation(s)
- A Stefanidis
- Department of Physiology, Monash University, Clayton, VIC, Australia
| | - B J Oldfield
- Metabolic Disease and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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24
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Li W, Richard D. Effects of Bariatric Surgery on Energy Homeostasis. Can J Diabetes 2017; 41:426-431. [DOI: 10.1016/j.jcjd.2017.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/11/2017] [Accepted: 05/04/2017] [Indexed: 12/11/2022]
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25
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Palmiter RD. Neural Circuits That Suppress Appetite: Targets for Treating Obesity? Obesity (Silver Spring) 2017; 25:1299-1301. [PMID: 28677241 DOI: 10.1002/oby.21886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/03/2017] [Accepted: 05/03/2017] [Indexed: 11/12/2022]
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26
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Hankir MK, Patt M, Patt JTW, Becker GA, Rullmann M, Kranz M, Deuther-Conrad W, Schischke K, Seyfried F, Brust P, Hesse S, Sabri O, Krügel U, Fenske WK. Suppressed Fat Appetite after Roux-en-Y Gastric Bypass Surgery Associates with Reduced Brain μ-opioid Receptor Availability in Diet-Induced Obese Male Rats. Front Neurosci 2017; 10:620. [PMID: 28133443 PMCID: PMC5233681 DOI: 10.3389/fnins.2016.00620] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/30/2016] [Indexed: 01/02/2023] Open
Abstract
Brain μ-opioid receptors (MORs) stimulate high-fat (HF) feeding and have been implicated in the distinct long term outcomes on body weight of bariatric surgery and dieting. Whether alterations in fat appetite specifically following these disparate weight loss interventions relate to changes in brain MOR signaling is unknown. To address this issue, diet-induced obese male rats underwent either Roux-en-Y gastric bypass (RYGB) or sham surgeries. Postoperatively, animals were placed on a two-choice diet consisting of low-fat (LF) and HF food and sham-operated rats were further split into ad libitum fed (Sham-LF/HF) and body weight-matched (Sham-BWM) to RYGB groups. An additional set of sham-operated rats always only on a LF diet (Sham-LF) served as lean controls, making four experimental groups in total. Corresponding to a stage of weight loss maintenance for RYGB rats, two-bottle fat preference tests in conjunction with small-animal positron emission tomography (PET) imaging studies with the selective MOR radioligand [11C]carfentanil were performed. Brains were subsequently collected and MOR protein levels in the hypothalamus, striatum, prefrontal cortex and orbitofrontal cortex were analyzed by Western Blot. We found that only the RYGB group presented with intervention-specific changes: having markedly suppressed intake and preference for high concentration fat emulsions, a widespread reduction in [11C]carfentanil binding potential (reflecting MOR availability) in various brain regions, and a downregulation of striatal and prefrontal MOR protein levels compared to the remaining groups. These findings suggest that the suppressed fat appetite caused by RYGB surgery is due to reduced brain MOR signaling, which may contribute to sustained weight loss unlike the case for dieting.
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Affiliation(s)
- Mohammed K Hankir
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of Leipzig Leipzig, Germany
| | - Marianne Patt
- Department of Nuclear Medicine, University of Leipzig Leipzig, Germany
| | - Jörg T W Patt
- Department of Nuclear Medicine, University of Leipzig Leipzig, Germany
| | - Georg A Becker
- Department of Nuclear Medicine, University of Leipzig Leipzig, Germany
| | - Michael Rullmann
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of LeipzigLeipzig, Germany; Department of Nuclear Medicine, University of LeipzigLeipzig, Germany
| | - Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig Leipzig, Germany
| | | | - Kristin Schischke
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of Leipzig Leipzig, Germany
| | - Florian Seyfried
- Department of General and Visceral, Vascular and Paediatric Surgery, University of Würzburg Würzburg, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Research Site Leipzig Leipzig, Germany
| | - Swen Hesse
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of LeipzigLeipzig, Germany; Department of Nuclear Medicine, University of LeipzigLeipzig, Germany
| | - Osama Sabri
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of LeipzigLeipzig, Germany; Department of Nuclear Medicine, University of LeipzigLeipzig, Germany
| | - Ute Krügel
- Rudolf-Boehm Institute of Pharmacology and Toxicology, University of Leipzig Leipzig, Germany
| | - Wiebke K Fenske
- Department of Medicine, Integrated Research and Treatment Centre for Adiposity Diseases, University of Leipzig Leipzig, Germany
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de Lartigue G, Diepenbroek C. Novel developments in vagal afferent nutrient sensing and its role in energy homeostasis. Curr Opin Pharmacol 2016; 31:38-43. [PMID: 27591963 DOI: 10.1016/j.coph.2016.08.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/01/2016] [Accepted: 08/11/2016] [Indexed: 12/16/2022]
Abstract
Vagal afferent neurons (VANs) play an important role in the control of food intake by signaling nutrient type and quantity to the brain. Recent findings are broadening our view of how VANs impact not only food intake but also energy homeostasis. This review focuses exclusively on studies of the vagus nerve from the past 2 years that highlight major new advancements in the field. We firstly discuss evidence that VANs can directly sense nutrients, and we consider new insights into mechanisms affecting sensing of gastric distension and signaling by gastrointestinal hormones ghrelin and GLP1. We discuss evidence that disrupting vagal afferent signaling increases long-term control of food intake and body weight management, and the importance of this gut-brain pathway in mediating beneficial effects of bariatric surgery. We conclude by highlighting novel roles for vagal afferent neurons in circadian rhythm, thermogenesis, and reward that may provide insight into mechanisms by which VAN nutrient sensing controls long-term control of energy homeostasis.
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Affiliation(s)
- Guillaume de Lartigue
- The John B. Pierce Laboratory, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Charlene Diepenbroek
- The John B. Pierce Laboratory, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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28
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Lutz TA, Bueter M. The Use of Rat and Mouse Models in Bariatric Surgery Experiments. Front Nutr 2016; 3:25. [PMID: 27547753 PMCID: PMC4974272 DOI: 10.3389/fnut.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 07/26/2016] [Indexed: 12/11/2022] Open
Abstract
Animal models have been proven to be a crucial tool for investigating the physiological mechanisms underlying bariatric surgery in general and individual techniques in particular. By using a translational approach, most of these studies have been performed in rodents and have helped to understand how bariatric surgery may or may not work. However, data from studies using animal models should always be critically evaluated for their transferability to the human physiology. It is, therefore, the aim of this review to summarize both advantages and limitations of data generated by animal based experiments designed to investigate and understand the physiological mechanisms at the root of bariatric surgery.
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Affiliation(s)
- Thomas A Lutz
- Vetsuisse Faculty, Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Marco Bueter
- Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; Department of Surgery, Division of Visceral and Transplant Surgery, University Hospital Zurich, Zurich, Switzerland
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