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Leinen M, Grandy EF, Gebel LMU, Santana TM, Rodriguez AL, Singh SK, Fernandez MI, Dalugdug JC, Garcia-Colon EM, Lybeshari K, Alexander DR, Maura MI, Gonzalez MDC, De Paula Cunha Almeida C, Anyaso-Samuel S, Datta S, Schiefer MA. Bilateral Subdiaphragmatic Vagal Nerve Stimulation Using a Novel Waveform Decreases Body Weight, Food Consumption, Adiposity, and Activity in Obesity-Prone Rats. Obes Surg 2024; 34:1-14. [PMID: 38040984 PMCID: PMC10781827 DOI: 10.1007/s11695-023-06957-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/05/2023] [Accepted: 11/13/2023] [Indexed: 12/03/2023]
Abstract
INTRODUCTION Obesity affects millions of Americans. The vagal nerves convey the degree of stomach fullness to the brain via afferent visceral fibers. Studies have found that vagal nerve stimulation (VNS) promotes reduced food intake, causes weight loss, and reduces cravings and appetite. METHODS Here, we evaluate the efficacy of a novel stimulus waveform applied bilaterally to the subdiaphragmatic vagal nerve stimulation (sVNS) for almost 13 weeks. A stimulating cuff electrode was implanted in obesity-prone Sprague Dawley rats maintained on a high-fat diet. Body weight, food consumption, and daily movement were tracked over time and compared against three control groups: sham rats on a high-fat diet that were implanted with non-operational cuffs, rats on a high-fat diet that were not implanted, and rats on a standard diet that were not implanted. RESULTS Results showed that rats on a high-fat diet that received sVNS attained a similar weight to rats on a standard diet due primarily to a reduction in daily caloric intake. Rats on a high-fat diet that received sVNS had significantly less body fat than other high-fat controls. Rats receiving sVNS also began moving a similar amount to rats on the standard diet. CONCLUSION Results from this study suggest that bilateral subdiaphragmatic vagal nerve stimulation can alter the rate of growth of rats maintained on a high-fat diet through a reduction in daily caloric intake, returning their body weight to that which is similar to rats on a standard diet over approximately 13 weeks.
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Affiliation(s)
- Monique Leinen
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Elise F Grandy
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Lourdes M Ubeira Gebel
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Tahimi Machin Santana
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Amanda L Rodriguez
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Sundip K Singh
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Michael I Fernandez
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Justin C Dalugdug
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Elaine M Garcia-Colon
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Kamela Lybeshari
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Daniel R Alexander
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Maria I Maura
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | - Maria D Cabrera Gonzalez
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA
| | | | - Samuel Anyaso-Samuel
- Department of Biostatistics, University of Florida, 2004 Mowry Rd, 5Th Fl, Gainesville, FL, 32603, USA
| | - Somnath Datta
- Department of Biostatistics, University of Florida, 2004 Mowry Rd, 5Th Fl, Gainesville, FL, 32603, USA
| | - Matthew A Schiefer
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, 1601 SW Archer Rd, Gainesville, FL, 32608, USA.
- Department of Biomedical Engineering, University of Florida, 1275 Center Dr, Gainesville, FL, 32611, USA.
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2
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Page AJ. Plasticity of gastrointestinal vagal afferents in terms of feeding-related physiology and pathophysiology. J Physiol 2023. [PMID: 37737742 DOI: 10.1113/jp284075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Gastrointestinal vagal afferents play an important role in communicating food related information from the gut to the brain. This information initiates vago-vagal reflexes essential for gut functions, including gut motility and secretions. These afferents also play a role in energy homeostasis, signalling the arrival, amount and nutrient composition of a meal to the central nervous system where it is processed ultimately leading to termination of a meal. Vagal afferent responses to food related stimuli demonstrate a high degree of plasticity, responding to short term changes in nutritional demand, such as the fluctuations that occur across a 24-hr or in response to a fast, as well as long term changes in energy demand, such as occurs during pregnancy. This plasticity is disrupted in disease states, such as obesity or chronic stress where there is hypo- and hypersensitivity of these afferents, respectively. Improved understanding of the plasticity of these afferents will enable identification of new treatment options for diseases associated with vagal afferent function.
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Affiliation(s)
- Amanda J Page
- Vagal Afferent Research Group, School of Biomedicine, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, SAHMRI, Adelaide, South Australia, Australia
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3
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Peiris M, Aktar R, Reed D, Cibert-Goton V, Zdanaviciene A, Halder W, Robinow A, Corke S, Dogra H, Knowles CH, Blackshaw A. Decoy bypass for appetite suppression in obese adults: role of synergistic nutrient sensing receptors GPR84 and FFAR4 on colonic endocrine cells. Gut 2022; 71:928-937. [PMID: 34083384 PMCID: PMC8995825 DOI: 10.1136/gutjnl-2020-323219] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 05/09/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Colonic enteroendocrine cells (EECs) store and release potent anorectic hormones that are key regulators of satiety. EECs express multiple nutrient sensing receptors, particularly for medium-chain fatty acids (MCFAs): GPR84 and FFAR4. Here we show a non-surgical approach with targeted colonic delivery of MCFA, which induces EEC and neuronal activation leading to anorectic effects. DESIGN A randomised, double-blind, placebo-controlled, cross-over study was performed in obese adults given combined GPR84 and FFAR4 agonists in colonic release capsules before meals. We measured serum hormones, energy intake and appetite perception. Cell type, activation by agonists and hormone/serotonin release were determined in human colonic explants. Mouse colonic afferent nerve responses to nutrients/mediators were recorded electrophysiologically. RESULTS Subjects receiving GPR84 and FFAR4 agonists had reduced overall calorific intake and increased postprandial levels of PYY versus placebo. Receptors including GPR84 and FFAR4 were coexpressed on human colonic EEC. Activation of GPR84 exclusively induced intracellular pERK, whereas FFAR4 selectively activated pCaMKII. Coactivation of GPR84 and FFAR4 induced both phosphoproteins, and superadditive release of GLP-1 and PYY. Nutrients and hormones convergently activated murine colonic afterent nerves via GLP-1, Y2 and 5-HT3 receptors. CONCLUSIONS Colonic GPR84 and FFAR4 agonists reduce energy intake and increase postprandial PYY in obese adults. Human colonic EECs coexpress these receptors, which activate cells via parallel intracellular pathways and synergistically evoke hormone release. Further synergism occurs in sensory nerve responses to MCFA and EEC mediators. Thus, synergistic activation of colonic endocrine cells via nutrient receptors is an important target for metabolic regulation. TRAIL REGISTRATION NUMBER NCT04292236.
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Affiliation(s)
- Madusha Peiris
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Rubina Aktar
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David Reed
- Gastrointestinal Diseases Research, Queen's University, Kingston, Queensland, Canada
| | - Vincent Cibert-Goton
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ausra Zdanaviciene
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Writaja Halder
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Adam Robinow
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Simon Corke
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Harween Dogra
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Charles H Knowles
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ashley Blackshaw
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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Mechanisms of reduced leptin-mediated satiety signaling during obesity. Int J Obes (Lond) 2022; 46:1212-1221. [PMID: 35241786 DOI: 10.1038/s41366-022-01079-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/17/2021] [Accepted: 01/17/2022] [Indexed: 11/08/2022]
Abstract
BACKGROUND/OBJECTIVES Disrupted leptin signaling in vagal afferent neurons contributes to hyperphagia and obesity. Thus, we tested the hypothesis that intrinsic negative regulators of leptin signaling, suppressor of cytokine signaling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) underlie dysfunctional leptin-mediated vagal afferent satiety signaling during obesity. METHODS Experiments were performed on standard chow-fed control mice, high-fat fed (HFF), or low-fat fed (LFF) mice. SOCS3 and PTP1B expression were quantified using western blot and quantitative PCR. Nodose ganglion neuronal excitability and jejunal afferent sensitivity were measured by patch clamp and extracellular afferent recordings, respectively. RESULTS Increased expression of SOCS3 and PTP1B were observed in the jejunum of HFF mice. Prolonged incubation with leptin attenuated nodose ganglion neuronal excitability, and this effect was reversed by inhibition of SOCS3. Leptin potentiated jejunal afferent nerve responses to CCK in LFF mice but decreased them in HFF mice. Inhibition of SOCS3 restored impaired vagal afferent neuronal excitability and afferent nerve responses to satiety mediators during obesity. Two-pore domain K+ channel (K2P) conductance and nitric oxide (NO) production that we previously demonstrated were elevated during obesity were decreased by inhibitions of SOCS3 or PTP1B. CONCLUSIONS This study suggests that obesity impairs vagal afferent sensitivity via SOCS3 and PTP1B, likely as a consequence of obesity-induced hyperleptinemia. The mechanisms underlying leptin resistance appear also to cause a more global impairment of satiety-related vagal afferent responsiveness.
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Neural signalling of gut mechanosensation in ingestive and digestive processes. Nat Rev Neurosci 2022; 23:135-156. [PMID: 34983992 DOI: 10.1038/s41583-021-00544-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2021] [Indexed: 12/29/2022]
Abstract
Eating and drinking generate sequential mechanosensory signals along the digestive tract. These signals are communicated to the brain for the timely initiation and regulation of diverse ingestive and digestive processes - ranging from appetite control and tactile perception to gut motility, digestive fluid secretion and defecation - that are vital for the proper intake, breakdown and absorption of nutrients and water. Gut mechanosensation has been investigated for over a century as a common pillar of energy, fluid and gastrointestinal homeostasis, and recent discoveries of specific mechanoreceptors, contributing ion channels and the well-defined circuits underlying gut mechanosensation signalling and function have further expanded our understanding of ingestive and digestive processes at the molecular and cellular levels. In this Review, we discuss our current understanding of the generation of mechanosensory signals from the digestive periphery, the neural afferent pathways that relay these signals to the brain and the neural circuit mechanisms that control ingestive and digestive processes, focusing on the four major digestive tract parts: the oral and pharyngeal cavities, oesophagus, stomach and intestines. We also discuss the clinical implications of gut mechanosensation in ingestive and digestive disorders.
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Malczyk Ż, Roczniak W, Mazur B, Kwiecień J, Ziora K, Górska-Flak K, Oświęcimska J. Exocrine Pancreatic Function in Girls with Anorexia Nervosa. Nutrients 2021; 13:3280. [PMID: 34579156 PMCID: PMC8465751 DOI: 10.3390/nu13093280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/08/2021] [Accepted: 09/16/2021] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To assess pancreatic exocrine function in patients with anorexia nervosa using a breath test with 13C-labeled mixed triglycerides (MTG-BT) and to determine the relationship between the test results and selected biochemical and hormonal parameters. MATERIAL AND METHODS Anthropometric measurements, biochemical and hormonal parameters (serum leptin, soluble leptin receptor (sLR), acylated and desacylated ghrelin, free leptin index (FLI)), and MTG-BT were performed in a group of 31 girls with the restrictive type of AN, as well as 38 healthy girls (C). RESULTS The average cumulative dose of 13C-triglycerides recovered with exhaled air (%CD) was similar in both study groups, while the average time from 13C-triglycerides administration to peak 13CO2 excretion in expired air (time to peak (TTP)) was significantly longer in patients with AN compared to C. In both groups, %CD correlated negatively with FLI. TTP correlated negatively with sLR and FLI in the AN and with serum insulin and HOMA-IR values in the C. CONCLUSIONS In girls with AN, the pancreatic efficiency of lipase secretion was found to be normal, while the kinetics of this enzyme secretion were disturbed. These changes may result from disorders in the functioning of the adipose-insular and islet-acinar axes.
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Affiliation(s)
- Żaneta Malczyk
- Chair and Department of Pediatrics, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, ul. 3 Maja 13/15, 41-800 Zabrze, Poland; (J.K.); (K.Z.)
| | - Wojciech Roczniak
- Institute of Medicine, Jan Grodek State University in Sanok, ul. Mickiewicza 21, 38-500 Sanok, Poland; (W.R.); (J.O.)
| | - Bogdan Mazur
- Department of Microbiology and Immunology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, ul. Jordana 19, 41-808 Zabrze, Poland;
| | - Jarosław Kwiecień
- Chair and Department of Pediatrics, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, ul. 3 Maja 13/15, 41-800 Zabrze, Poland; (J.K.); (K.Z.)
| | - Katarzyna Ziora
- Chair and Department of Pediatrics, Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, ul. 3 Maja 13/15, 41-800 Zabrze, Poland; (J.K.); (K.Z.)
| | - Karolina Górska-Flak
- Department of Pediatrics, Institute of Medicine, University of Opole, Al. Wincentego Witosa 26, 45-401 Opole, Poland;
| | - Joanna Oświęcimska
- Institute of Medicine, Jan Grodek State University in Sanok, ul. Mickiewicza 21, 38-500 Sanok, Poland; (W.R.); (J.O.)
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The Function of Gastrointestinal Hormones in Obesity-Implications for the Regulation of Energy Intake. Nutrients 2021; 13:nu13061839. [PMID: 34072172 PMCID: PMC8226753 DOI: 10.3390/nu13061839] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 02/07/2023] Open
Abstract
The global burden of obesity and the challenges of prevention prompted researchers to investigate the mechanisms that control food intake. Food ingestion triggers several physiological responses in the digestive system, including the release of gastrointestinal hormones from enteroendocrine cells that are involved in appetite signalling. Disturbed regulation of gut hormone release may affect energy homeostasis and contribute to obesity. In this review, we summarize the changes that occur in the gut hormone balance during the pre- and postprandial state in obesity and the alterations in the diurnal dynamics of their plasma levels. We further discuss how obesity may affect nutrient sensors on enteroendocrine cells that sense the luminal content and provoke alterations in their secretory profile. Gastric bypass surgery elicits one of the most favorable metabolic outcomes in obese patients. We summarize the effect of different strategies to induce weight loss on gut enteroendocrine function. Although the mechanisms underlying obesity are not fully understood, restoring the gut hormone balance in obesity by targeting nutrient sensors or by combination therapy with gut peptide mimetics represents a novel strategy to ameliorate obesity.
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8
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Loper H, Leinen M, Bassoff L, Sample J, Romero-Ortega M, Gustafson KJ, Taylor DM, Schiefer MA. Both high fat and high carbohydrate diets impair vagus nerve signaling of satiety. Sci Rep 2021; 11:10394. [PMID: 34001925 PMCID: PMC8128917 DOI: 10.1038/s41598-021-89465-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/26/2021] [Indexed: 11/23/2022] Open
Abstract
Obesity remains prevalent in the US. One potential treatment is vagus nerve stimulation (VNS), which activates the sensory afferents innervating the stomach that convey stomach volume and establish satiety. However, current VNS approaches and stimulus optimization could benefit from additional understanding of the underlying neural response to stomach distension. In this study, obesity-prone Sprague Dawley rats consumed a standard, high-carbohydrate, or high-fat diet for several months, leading to diet-induced obesity in the latter two groups. Under anesthesia, the neural activity in the vagus nerve was recorded with a penetrating microelectrode array while the stomach was distended with an implanted balloon. Vagal tone during distension was compared to baseline tone prior to distension. Responses were strongly correlated with stomach distension, but the sensitivity to distension was significantly lower in animals that had been fed the nonstandard diets. The results indicate that both high fat and high carbohydrate diets impair vagus activity.
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Affiliation(s)
- Hailley Loper
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Monique Leinen
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Logan Bassoff
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Jack Sample
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,College of Medicine & Life Sciences, University of Toledo, Toledo, OH, USA
| | - Mario Romero-Ortega
- Departments of Biomedical Engineering and Biomedical Sciences, University of Houston, Houston, TX, USA
| | - Kenneth J Gustafson
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Dawn M Taylor
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.,Department of Neurosciences, The Cleveland Clinic, Cleveland, OH, USA
| | - Matthew A Schiefer
- Malcom Randall VA Medical Center, Gainesville, FL, USA. .,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA. .,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
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Xing JW, Chen MM, Tian XY, Pan DQ, Peng XH, Gao PF. 919 syrup inhibits ROS-mediated leptin-induced anorexia by activating PPARγ and improves gut flora abnormalities. Biomed Pharmacother 2021; 138:111455. [PMID: 33711553 DOI: 10.1016/j.biopha.2021.111455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/26/2021] [Accepted: 02/27/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Women with postpartum psychiatric disorders are prone to severe anorexia. Clinical studies have revealed the efficacy of 919 syrup, a traditional Chinese medicine mixture against postpartum illnesses, such as in regulating maternal mood and improving postpartum anorexia. AIM This study investigated the mechanisms through which 919 syrup improved anorexia induced by postpartum stress, focussing on the combined peroxisome proliferator-activated receptor gamma (PPARγ) and leptin signalling pathway, and its effects on the structure of the gut flora. METHODS Mice were randomly divided into five groups-control group, immobilisation stressed (IS) group (normal saline), pioglitazone (Piog; western medicine control) group, 919 syrup low-dose (TJD; 13.5 g/kg) group, and 919 syrup high-dose (TJG; 27.0 g/kg) group. The control group was housed normally. The other groups received IS for 3 h daily for 21 days. The treatments were initiated following the first postnatal day and were administered by gastric gavage. All mice were sacrificed under anaesthesia on postnatal day 22. Blood, hypothalamus, stomach, and faecal specimens were collected. Gene and protein expression levels of components of the PPARγ-leptin signalling pathway in the serum, hypothalamus, and stomach were determined. Immunofluorescence staining for proopiomelanocortin (POMC), phosphorylated signal transducer and activator of transcription 3 (pSTAT3), and leptin was performed to observe their spatial distributions in the hypothalamus and stomach. 16s rRNA gene sequencing and bioinformatics analysis of fecal specimens were performed. RESULTS After IS, postpartum mice showed significantly reduced appetite and body weight, accompanied by abnormalities in the structure of the gut flora. Treatment with 919 syrup (27.0 g/kg) downregulated malondialdehyde and upregulated catalase, glutathione peroxidase, and superoxide dismutase by activating PPARγ, thereby affecting the expression of leptin signalling pathway components (leptin, leptin receptor, pSTAT3, POMC, and cocaine and amphetamine-related transcript and neuropeptide Y), and modulated the gut flora in stressed mice. CONCLUSION 919 syrup improved appetite in mice with postnatal stress by activating PPARγ to induce crosstalk with the leptin signalling pathway, this mechanism was similar to that of PPARγ agonists. 919 syrup also improved gut flora structure, and the changes in the relative abundances of the gut flora strongly correlated with the expression levels of PPARγ and leptin pathway components.
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Affiliation(s)
- Jing-Wei Xing
- Department of Traditional Chinese Medicine, Jinshan Hospital of Fudan University, Shanghai, China
| | - Man-Man Chen
- Department of Traditional Chinese Medicine, Huashan Hospital of Fudan University, Shanghai, China
| | - Xin-Yun Tian
- Department of Traditional Chinese Medicine, Jinshan Hospital of Fudan University, Shanghai, China
| | - Dan-Qing Pan
- Department of Traditional Chinese Medicine, Jinshan Hospital of Fudan University, Shanghai, China
| | - Xiu-Hua Peng
- Department of Animal Experiments, Shanghai Public Health Clinical Center, Shanghai, China
| | - Peng-Fei Gao
- Department of Traditional Chinese Medicine, Jinshan Hospital of Fudan University, Shanghai, China.
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McDougle M, Quinn D, Diepenbroek C, Singh A, de la Serre C, de Lartigue G. Intact vagal gut-brain signalling prevents hyperphagia and excessive weight gain in response to high-fat high-sugar diet. Acta Physiol (Oxf) 2021; 231:e13530. [PMID: 32603548 PMCID: PMC7772266 DOI: 10.1111/apha.13530] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/02/2023]
Abstract
Aim The tools that have been used to assess the function of the vagus nerve lack specificity. This could explain discrepancies about the role of vagal gut‐brain signalling in long‐term control of energy balance. Here we use a validated approach to selectively ablate sensory vagal neurones that innervate the gut to determine the role of vagal gut‐brain signalling in the control of food intake, energy expenditure and glucose homoeostasis in response to different diets. Methods Rat nodose ganglia were injected bilaterally with either the neurotoxin saporin conjugated to the gastrointestinal hormone cholecystokinin (CCK), or unconjugated saporin as a control. Food intake, body weight, glucose tolerance and energy expenditure were measured in both groups in response to chow or high‐fat high‐sugar (HFHS) diet. Willingness to work for fat or sugar was assessed by progressive ratio for orally administered solutions, while post‐ingestive feedback was tested by measuring food intake after an isocaloric lipid or sucrose pre‐load. Results Vagal deafferentation of the gut increases meal number in lean chow‐fed rats. Switching to a HFHS diet exacerbates overeating and body weight gain. The breakpoint for sugar or fat solution did not differ between groups, suggesting that increased palatability may not drive HFHS‐induced hyperphagia. Instead, decreased satiation in response to intra‐gastric infusion of fat, but not sugar, promotes hyperphagia in CCK‐Saporin‐treated rats fed with HFHS diet. Conclusions We conclude that intact sensory vagal neurones prevent hyperphagia and exacerbation of weight gain in response to a HFHS diet by promoting lipid‐mediated satiation.
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Affiliation(s)
- Molly McDougle
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
| | | | - Charlene Diepenbroek
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
| | - Arashdeep Singh
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
| | | | - Guillaume de Lartigue
- Department of Pharmacodynamics University of Florida Gainesville FL USA
- Center for Integrative Cardiovascular and Metabolic Disease University of Florida Gainesville FL USA
- The John B. Pierce Laboratory New Haven CT USA
- Department of Cellular and Molecular Physiology Yale Medical School New Haven CT USA
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11
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Li H, Clarke GS, Christie S, Ladyman SR, Kentish SJ, Young RL, Gatford KL, Page AJ. Pregnancy-related plasticity of gastric vagal afferent signals in mice. Am J Physiol Gastrointest Liver Physiol 2021; 320:G183-G192. [PMID: 33206550 DOI: 10.1152/ajpgi.00357.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric vagal afferents (GVAs) sense food-related mechanical stimuli and signal to the central nervous system, to integrate control of meal termination. Pregnancy is characterized by increased maternal food intake, which is essential for normal fetal growth and to maximize progeny survival and health. However, it is unknown whether GVA function is altered during pregnancy to promote food intake. This study aimed to determine the mechanosensitivity of GVAs and food intake during early, mid-, and late stages of pregnancy in mice. Pregnant mice consumed more food compared with nonpregnant mice, notably in the light phase during mid- and late pregnancy. The increased food intake was predominantly due to light-phase increases in meal size across all stages of pregnancy. The sensitivity of GVA tension receptors to gastric distension was significantly attenuated in mid- and late pregnancy, whereas the sensitivity of GVA mucosal receptors to mucosal stroking was unchanged during pregnancy. To determine whether pregnancy-associated hormonal changes drive these adaptations, the effects of estradiol, progesterone, prolactin, and growth hormone on GVA tension receptor mechanosensitivity were determined in nonpregnant female mice. The sensitivity of GVA tension receptors to gastric distension was augmented by estradiol, attenuated by growth hormone, and unaffected by progesterone or prolactin. Together, the data indicate that the sensitivity of GVA tension receptors to tension is reduced during pregnancy, which may attenuate the perception of gastric fullness and explain increased food intake. Further, these adaptations may be driven by increases in maternal circulating growth hormone levels during pregnancy.NEW & NOTEWORTHY This study provides first evidence that gastric vagal afferent signaling is attenuated during pregnancy and inversely associated with meal size. Growth hormone attenuated mechanosensitivity of gastric vagal afferents, adding support that increases in maternal growth hormone may mediate adaptations in gastric vagal afferent signaling during pregnancy. These findings have important implications for the peripheral control of food intake during pregnancy.
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Affiliation(s)
- Hui Li
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Georgia S Clarke
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Stewart Christie
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Sharon R Ladyman
- Department of Anatomy, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - Stephen J Kentish
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Kathryn L Gatford
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia
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12
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Xie H, Yepuri N, Meng Q, Dhawan R, Leech CA, Chepurny OG, Holz GG, Cooney RN. Therapeutic potential of α7 nicotinic acetylcholine receptor agonists to combat obesity, diabetes, and inflammation. Rev Endocr Metab Disord 2020; 21:431-447. [PMID: 32851581 PMCID: PMC7572644 DOI: 10.1007/s11154-020-09584-3] [Citation(s) in RCA: 20] [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] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
The cholinergic anti-inflammatory reflex (CAIR) represents an important homeostatic regulatory mechanism for sensing and controlling the body's response to inflammatory stimuli. Vagovagal reflexes are an integral component of CAIR whose anti-inflammatory effects are mediated by acetylcholine (ACh) acting at α7 nicotinic acetylcholine receptors (α7nAChR) located on cells of the immune system. Recently, it is appreciated that CAIR and α7nAChR also participate in the control of metabolic homeostasis. This has led to the understanding that defective vagovagal reflex circuitry underlying CAIR might explain the coexistence of obesity, diabetes, and inflammation in the metabolic syndrome. Thus, there is renewed interest in the α7nAChR that mediates CAIR, particularly from the standpoint of therapeutics. Of special note is the recent finding that α7nAChR agonist GTS-21 acts at L-cells of the distal intestine to stimulate the release of two glucoregulatory and anorexigenic hormones: glucagon-like peptide-1 (GLP-1) and peptide YY (PYY). Furthermore, α7nAChR agonist PNU 282987 exerts trophic factor-like actions to support pancreatic β-cell survival under conditions of stress resembling diabetes. This review provides an overview of α7nAChR function as it pertains to CAIR, vagovagal reflexes, and metabolic homeostasis. We also consider the possible usefulness of α7nAChR agonists for treatment of obesity, diabetes, and inflammation.
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Affiliation(s)
- Han Xie
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Natesh Yepuri
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Qinghe Meng
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Ravi Dhawan
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Colin A Leech
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA
| | - Oleg G Chepurny
- Departments of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - George G Holz
- Departments of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Robert N Cooney
- Departments of Surgery, State University of New York (SUNY), Upstate Medical University, 750 E Adams St., Suite 8141, Syracuse, NY, 13210, USA.
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13
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Huang KP, Goodson ML, Vang W, Li H, Page AJ, Raybould HE. Leptin signaling in vagal afferent neurons supports the absorption and storage of nutrients from high-fat diet. Int J Obes (Lond) 2020; 45:348-357. [PMID: 32917985 PMCID: PMC7854885 DOI: 10.1038/s41366-020-00678-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/30/2020] [Accepted: 09/03/2020] [Indexed: 12/18/2022]
Abstract
Objective: Activation of vagal afferent neurons (VAN) by postprandial gastrointestinal signals terminates feeding and facilitates nutrient digestion and absorption. Leptin modulates responsiveness of VAN to meal-related gastrointestinal signals. Rodents with high-fat diet (HF) feeding develop leptin resistance that impairs responsiveness of VAN. We hypothesized that lack of leptin signaling in VAN reduces responses to meal-related signals, which in turn decreases absorption of nutrients and energy storage from high-fat, calorically dense food. Methods: Mice with conditional deletion of the leptin receptor from VAN (Nav1.8-Cre/LepRfl/fl; KO) were used in this study. Six-week-old male mice were fed a 45% HF for 4 weeks; metabolic phenotype, food intake, and energy expenditure were measured. Absorption and storage of nutrients were investigated in the refed state. Results: After 4 weeks of HF feeding, KO mice gained less body weight and fat mass that WT controls, but this was not due to differences in food intake or energy expenditure. KO mice had reduced expression of carbohydrate transporters and absorption of carbohydrate in the jejunum. KO mice had fewer hepatic lipid droplets and decreased expression of de novo lipogenesis-associated enzymes and lipoproteins for endogenous lipoprotein pathway in liver, suggesting decreased long-term storage of carbohydrate in KO mice. Conclusions: Impairment of leptin signaling in VAN reduces responsiveness to gastrointestinal signals, which reduces intestinal absorption of carbohydrates and de novo lipogenesis resulting in reduced long-term energy storage. This study reveals a novel role of vagal afferents to support digestion and energy storage that may contribute to the effectiveness of vagal blockade to induce weight loss.
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Affiliation(s)
- Kuei-Pin Huang
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Michael L Goodson
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Wendie Vang
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Hui Li
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Helen E Raybould
- School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
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14
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Koliaki C, Liatis S, Dalamaga M, Kokkinos A. The Implication of Gut Hormones in the Regulation of Energy Homeostasis and Their Role in the Pathophysiology of Obesity. Curr Obes Rep 2020; 9:255-271. [PMID: 32647952 DOI: 10.1007/s13679-020-00396-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW This review provides an update on the role of gut hormones and their interactions in the regulation of energy homeostasis, describes gut hormone adaptations in obesity and in response to weight loss, and summarizes the current evidence on the role of gut hormone-based therapies for obesity treatment. RECENT FINDINGS Gut hormones play a key role in regulating eating behaviour, energy and glucose homeostasis. Dysregulated gut hormone responses have been proposed to be pathogenetically involved in the development and perpetuation of obesity. Summarizing the major gut hormone changes in obesity, obese individuals are characterized by blunted postprandial ghrelin suppression, loss of premeal ghrelin peaks, impaired diurnal ghrelin variability and reduced fasting and postprandial levels of anorexigenic peptides. Adaptive alterations of gut hormone levels are implicated in weight regain, thus complicating hypocaloric dietary interventions, and can further explain the profound weight loss and metabolic improvement following bariatric surgery. A plethora of compounds mimicking gut hormone changes after bariatric surgery are currently under investigation, introducing a new era in the pharmacotherapy of obesity. The current trend is to combine different gut hormone receptor agonists and target multiple systems simultaneously, in order to replicate as closely as possible the gut hormone milieu after bariatric surgery and circumvent the counter-regulatory adaptive changes associated with dietary energy restriction. An increasing number of preclinical and early-phase clinical trials reveal the additive benefits obtained with dual or triple gut peptide receptor agonists in reducing body weight and improving glycaemia. Gut hormones act as potent regulators of energy and glucose homeostasis. Therapeutic strategies targeting their levels or receptors emerge as a promising approach to treat patients with obesity and hyperglycaemia.
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Affiliation(s)
- Chrysi Koliaki
- First Department of Propaedeutic Internal Medicine, Medical School, Laiko General Hospital, National Kapodistrian University of Athens, 17 Agiou Thoma Street, 11527, Athens, Greece.
| | - Stavros Liatis
- First Department of Propaedeutic Internal Medicine, Medical School, Laiko General Hospital, National Kapodistrian University of Athens, 17 Agiou Thoma Street, 11527, Athens, Greece
| | - Maria Dalamaga
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Alexander Kokkinos
- First Department of Propaedeutic Internal Medicine, Medical School, Laiko General Hospital, National Kapodistrian University of Athens, 17 Agiou Thoma Street, 11527, Athens, Greece
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15
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Lupien-Meilleur J, Andrich DE, Quinn S, Micaelli-Baret C, St-Amand R, Roy D, St-Pierre DH. Interplay Between Gut Microbiota and Gastrointestinal Peptides: Potential Outcomes on the Regulation of Glucose Control. Can J Diabetes 2020; 44:359-367. [DOI: 10.1016/j.jcjd.2019.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/11/2019] [Accepted: 10/16/2019] [Indexed: 12/12/2022]
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16
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Christie S, O'Rielly R, Li H, Nunez-Salces M, Wittert GA, Page AJ. Modulatory effect of methanandamide on gastric vagal afferent satiety signals depends on nutritional status. J Physiol 2020; 598:2169-2182. [PMID: 32237243 DOI: 10.1113/jp279449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/25/2020] [Indexed: 12/18/2022] Open
Abstract
SIGNIFICANCE STATEMENT Gastric vagal afferent responses to tension are dampened in high fat diet-induced obesity. Endocannabinoids are known to dose-dependently inhibit and excite gastric vagal afferents but their effect on gastric vagal afferents in diet-induced obesity are unknown. In individual gastric vagal afferent neurons of diet-induced obese mice the co-expression of components of the endocannabinoid system, including CB1, GHSR, TRPV1 and FAAH, was increased compared with lean mice. In high fat diet-induced obese mice, methanandamide only inhibited gastric vagal afferent responses to tension, possibly due to the observed change in the balance of receptors, hormones and breakdown enzymes in this system. Collectively, these data suggest that endocannabinoid signalling, by gastric vagal afferents, is altered in diet-induced obesity which may impact satiety and gastrointestinal function. ABSTRACT Gastric vagal afferents (GVAs) play a role in appetite regulation. The endocannabinoid anandamide (AEA) dose-dependently inhibits and excites tension-sensitive GVAs. However, it is also known that high fat diet (HFD) feeding alters GVA responses to stretch. The aim of this study was to determine the role of AEA in GVA signalling in lean and HFD-induced obese mice. Male C57BL/6 mice were fed (12 weeks) a standard laboratory diet (SLD) or HFD. Protein and mRNA expression of components of the cannabinoid system was determined in individual GVA cell bodies and the gastric mucosa. An in vitro GVA preparation was used to assess the effect of methanandamide (mAEA) on tension-sensitive GVAs and the second messenger pathways involved. In individual GVA cell bodies, cannabinoid 1 (CB1) and ghrelin (GHSR) receptor mRNA was higher in HFD mice than SLD mice. Conversely, gastric mucosal AEA and ghrelin protein levels were lower in HFD mice than SLD mice. In SLD mice, mAEA exerted dose-dependent inhibitory and excitatory effects on tension-sensitive GVAs. Only an inhibitory effect of mAEA was observed in HFD mice. The excitatory effect of mAEA was dependent on CB1, transient receptor potential vanilloid 1 (TRPV1) and the protein kinase C. Conversely, the inhibitory effect was dependent on CB1, growth hormone secretagogue receptor, TRPV1 and the protein kinase A. Endocannabinoids, acting through CB1 and TRPV1, have a pivotal role in modulating GVA satiety signals depending on the second messenger pathway utilised. In HFD mice only an inhibitory effect was observed. These changes may contribute to the development and/or maintenance of obesity.
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Affiliation(s)
- Stewart Christie
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Rebecca O'Rielly
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Maria Nunez-Salces
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Gary A Wittert
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
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17
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Circadian regulation of appetite and time restricted feeding. Physiol Behav 2020; 220:112873. [PMID: 32194073 DOI: 10.1016/j.physbeh.2020.112873] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/01/2020] [Accepted: 03/10/2020] [Indexed: 12/15/2022]
Abstract
The circadian system plays an important role in the temporal regulation of metabolic processes as well as food intake to ensure energy efficiency. The 'master' clock is located within the superchiasmatic nucleus and receives input from the retina so that it can be entrained by the light:dark cycle. In turn, the master clock entrains other clocks in the central nervous system, including areas involved in energy homeostasis such as the arcuate nucleus, and the periphery (e.g. adipose tissue and the gastrointestinal tract). This master clock is reinforced by other zeitgebers such as the timing of food intake and activity. If these zeitgebers desynchronise, such as occurs in high fat diet-induced obesity or shift work conditions, it can lead to a misalignment of circadian clocks, disruption of metabolic processes and the development of metabolic disorders. The timing of food intake is a strong zeitgeber, particularly in the gastrointestinal tract, and therefore time restricted feeding offers potential for the treatment of diet and shift work induced metabolic disorders. This review will focus on the role of the circadian system in food intake regulation and the effect of environment factors, such as high fat diet feeding or shift work, on the temporal regulation of food intake along with the benefits of time restricted feeding.
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18
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Obesity Affects the Microbiota-Gut-Brain Axis and the Regulation Thereof by Endocannabinoids and Related Mediators. Int J Mol Sci 2020; 21:ijms21051554. [PMID: 32106469 PMCID: PMC7084914 DOI: 10.3390/ijms21051554] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/21/2022] Open
Abstract
The hypothalamus regulates energy homeostasis by integrating environmental and internal signals to produce behavioral responses to start or stop eating. Many satiation signals are mediated by microbiota-derived metabolites coming from the gastrointestinal tract and acting also in the brain through a complex bidirectional communication system, the microbiota–gut–brain axis. In recent years, the intestinal microbiota has emerged as a critical regulator of hypothalamic appetite-related neuronal networks. Obesogenic high-fat diets (HFDs) enhance endocannabinoid levels, both in the brain and peripheral tissues. HFDs change the gut microbiota composition by altering the Firmicutes:Bacteroidetes ratio and causing endotoxemia mainly by rising the levels of lipopolysaccharide (LPS), the most potent immunogenic component of Gram-negative bacteria. Endotoxemia induces the collapse of the gut and brain barriers, interleukin 1β (IL1β)- and tumor necrosis factor α (TNFα)-mediated neuroinflammatory responses and gliosis, which alter the appetite-regulatory circuits of the brain mediobasal hypothalamic area delimited by the median eminence. This review summarizes the emerging state-of-the-art evidence on the function of the “expanded endocannabinoid (eCB) system” or endocannabinoidome at the crossroads between intestinal microbiota, gut-brain communication and host metabolism; and highlights the critical role of this intersection in the onset of obesity.
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19
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Minaya DM, Di Lorenzo PM, Hajnal A, Czaja K. Roux-en-Y gastric bypass surgery triggers rapid DNA fragmentation in vagal afferent neurons in rats. Acta Neurobiol Exp (Wars) 2020. [DOI: 10.21307/ane-2019-040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Browning KN. Stress-induced modulation of vagal afferents. Neurogastroenterol Motil 2019; 31:e13758. [PMID: 31736236 PMCID: PMC6986320 DOI: 10.1111/nmo.13758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/18/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022]
Abstract
Vagally dependent gastric functions, including motility, tone, compliance, and emptying rate, play an important role in the regulation of food intake and satiation. Vagal afferent fibers relay sensory information from the stomach, including meal-related information, centrally and initiate co-ordinated autonomic efferent responses that regulate upper gastrointestinal responses. The purpose of this mini-review is to highlight several recent studies which have uncovered the remarkable degree of neuroplasticity within gastric mechanosensitive vagal afferents and the recent study by Li et al, in this issue of Neurogastroenterology and Motility, who show that the mechanosensitivity of gastric vagal afferents is dysregulated in a murine model of chronic stress. The authors demonstrate that both gastric mucosal and tension afferents are hypersensitive following chronic stress, and responses to mucosal stroking and muscle stretch are enhanced significantly. As gastric distension and volumetric signaling is important in satiety signaling and meal termination, this may provide a mechanistic basis for the gastric hypersensitivity associated with stress-associated clinical problems such as functional dyspepsia.
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Affiliation(s)
- Kirsteen N. Browning
- Department of Neural and Behavioral Sciences Penn State College of Medicine Hershey Pennsylvania
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21
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Makaronidis JM, Batterham RL. The role of gut hormones in the pathogenesis and management of obesity. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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Kentish SJ, Christie S, Vincent A, Li H, Wittert GA, Page AJ. Disruption of the light cycle ablates diurnal rhythms in gastric vagal afferent mechanosensitivity. Neurogastroenterol Motil 2019; 31:e13711. [PMID: 31509314 DOI: 10.1111/nmo.13711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Gastric vagal afferents (GVAs) respond to mechanical stimulation, initiating satiety. These afferents exhibit diurnal fluctuations in mechanosensitivity, facilitating food intake during the dark phase in rodents. In humans, desynchrony of diurnal rhythms (eg, shift work) is associated with a higher risk of obesity. To test the hypothesis that shift work disrupts satiety signaling, the effect of a rotating light cycles on diurnal rhythms in GVA mechanosensitivity in lean and high-fat diet (HDF)-induced obese mice was determined. METHODS Male C57BL/6 mice were fed standard laboratory diet (SLD) or HFD for 12 weeks. After 4 weeks, mice were randomly allocated to a normal light (NL; 12 hour light: 12 hour dark; lights on at zeitgeber time [ZT] 0) or rotating light (RL; 3-day NL cycle, 4-day reversed light cycle [lights on: ZT12] repeated) cycle for 8 weeks. At week 12, eight mice from each group were housed in metabolic cages. After 12 weeks, ex vivo GVA recordings were taken at 3 hour intervals starting at ZT0. KEY RESULTS SLD-RL and HFD-RL gained more weight compared to SLD-NL and HFD-NL mice, respectively. Gonadal fat pad mass was higher in SLD-RL compared to SLD-NL mice. In SLD-NL mice, tension and mucosal receptor mechanosensitivity exhibited diurnal rhythms with a peak at ZT9. These rhythms were lost in SLD-RL, HFD-NL, and HFD-RL mice and associated with dampened diurnal rhythms in food intake. CONCLUSIONS & INFERENCES GVA diurnal rhythms are susceptible to disturbances in the light cycle and/or the obese state. This may underpin the observed changes in feeding behavior.
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Affiliation(s)
- Stephen J Kentish
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Stewart Christie
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Andrew Vincent
- Nutrition, Diabetes & Metabolism, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Freemasons Foundation Centre for Men's Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes & Metabolism, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Gary A Wittert
- Nutrition, Diabetes & Metabolism, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Freemasons Foundation Centre for Men's Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes & Metabolism, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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23
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Li H, Buisman-Pijlman FTA, Nunez-Salces M, Christie S, Frisby CL, Inserra A, Hatzinikolas G, Lewis MD, Kritas S, Wong ML, Page AJ. Chronic stress induces hypersensitivity of murine gastric vagal afferents. Neurogastroenterol Motil 2019; 31:e13669. [PMID: 31241809 DOI: 10.1111/nmo.13669] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/22/2019] [Accepted: 06/18/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Stress exposure is known to trigger and exacerbate functional dyspepsia (FD) symptoms. Increased gastric sensitivity to food-related stimuli is widely observed in FD patients and is associated with stress and psychological disorders. The mechanisms underlying the hypersensitivity are not clear. Gastric vagal afferents (GVAs) play an important role in sensing meal-related mechanical stimulation to modulate gastrointestinal function and food intake. This study aimed to determine whether GVAs display hypersensitivity after chronic stress, and whether its interaction with leptin was altered by stress. METHODS Eight-week-old male C57BL/6 mice were exposed to unpredictable chronic mild stress or no stress (control) for 8 weeks. The metabolic rate, gastric emptying rate, and anxiety- and depression-like behaviors were determined. GVA mechanosensitivity, and its modulation by leptin, was determined using an in vitro single fiber recording technique. QRT-PCR was used to establish the levels of leptin and leptin receptor mRNA in the stomach and nodose ganglion, respectively. KEY RESULTS The stressed mice had lower body weight and food intake, and increased anxiety-like behavior compared to the control mice. The mechanosensitivity of mucosal and tension-sensitive GVAs was higher in the stressed mice. Leptin potentiated mucosal GVA mechanosensitivity in control but not stressed mice. The expression of leptin mRNA in the gastric mucosa was lower in the stressed mice. CONCLUSIONS AND INFERENCES In conclusion, chronic stress enhances GVA mechanosensitivity, which may contribute to the gastric hypersensitivity in FD. In addition, the modulatory effect of leptin on GVA signaling is lost after chronic stress exposure.
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Affiliation(s)
- Hui Li
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Femke T A Buisman-Pijlman
- Behavioural Neuroscience, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Maria Nunez-Salces
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Stewart Christie
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Claudine L Frisby
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Antonio Inserra
- Neuropsychiatric Laboratory of Mental Health Disorder, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - George Hatzinikolas
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Martin D Lewis
- Neuropsychiatric Laboratory of Mental Health Disorder, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Stamatiki Kritas
- Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Ma-Li Wong
- Neuropsychiatric Laboratory of Mental Health Disorder, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Nutrition, Diabetes and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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Christie S, O'Rielly R, Li H, Wittert GA, Page AJ. Biphasic effects of methanandamide on murine gastric vagal afferent mechanosensitivity. J Physiol 2019; 598:139-150. [PMID: 31642519 DOI: 10.1113/jp278696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/20/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS The fine control of food intake is important for the maintenance of a healthy metabolic state. Gastric vagal afferents (GVAs) are involved in the peripheral regulation of food intake via signalling the degree of distension of the stomach which ultimately leads to feelings of fullness and satiety. This study provides evidence that endocannabinoids such as anandamide are capable of regulating GVA sensitivity in a concentration-dependent biphasic manner. This biphasic effect is dependent upon interactions between the CB1, TRPV1 and GHSR receptors. These data have important implications for the peripheral control of food intake. ABSTRACT Gastric vagal afferents (GVAs) signal to the hindbrain resulting in satiety. Endocannabinoids are endogenous ligands of cannabinoid 1 receptor (CB1) and transient receptor potential vanilloid-1 (TRPV1) channels. The endocannabinoid anandamide (AEA) is expressed in the stomach, and its receptor CB1 is expressed in ghrelin-positive gastric mucosal cells. Further, TRPV1, CB1 and growth hormone secretagogue receptor (ghrelin receptor, GHSR) are expressed in subpopulations of GVA neurons. This study aimed to determine the interaction between TRPV1, CB1, GHSR and endocannabinoids in the modulation of GVA signalling. An in vitro electrophysiology preparation was used to assess GVA mechanosensitivity in male C57BL/6 mice. Effects of methanandamide (mAEA; 1-100 nm), on GVA responses to stretch were determined in the absence and presence of antagonists of CB1, TRPV1, GHSR, protein kinase-A (PKA), protein kinase-C (PKC) and G-protein subunits Gαi/o , or Gαq . Low doses (1-10 nm) of mAEA reduced GVA responses to 3 g stretch, whereas high doses (30-100 nm) increased the response. The inhibitory and excitatory effects of mAEA (1-100 nm) were reduced/lost in the presence of a CB1 and TRPV1 antagonist. PKA, Gαi/o or GHSR antagonists prevented the inhibitory effect of mAEA on GVA mechanosensitivity. Conversely, in the presence of a PKC or Gαq antagonist the excitatory effect of mAEA was reduced or lost, respectively. Activation of CB1, by mAEA, can activate or inhibit TRPV1 to increase or decrease GVA responses to stretch, depending on the pathway activated. These interactions could play an important role in the fine control of food intake.
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Affiliation(s)
- Stewart Christie
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Rebecca O'Rielly
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Hui Li
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Lifelong Health, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Gary A Wittert
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Lifelong Health, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Lifelong Health, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
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Park J, Choi Y, Myoenzono K, Yoshikawa T, Tagawa K, Isobe T, Saotome K, Sankai Y, Shimojo N, Maeda S. Effects of aerobic exercise training on the arterial stiffness and intramyocellular or extramyocellular lipid in overweight and obese men. Clin Exp Hypertens 2019; 42:302-308. [PMID: 31392903 DOI: 10.1080/10641963.2019.1649686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) of ectopic fat in muscles are associated with arterial stiffness in normal-weight individuals. Furthermore, aerobic exercise training-induced changes in IMCL or EMCL content are related to a decrease in arterial stiffness in elderly people. Though arterial stiffness is strongly related with obesity, but the effects of aerobic exercise training on IMCL or EMCL content, with a particular focus on arterial stiffness, in obese individuals remains unclear. Here, we investigated the effects of aerobic exercise training on IMCL or EMCL content and arterial stiffness in obese individuals. First, in a cross-sectional study, we examined the relationship between arterial stiffness and IMCL or EMCL content in 24 overweight and obese men. Secondly, we investigated the effects of aerobic exercise intervention on arterial stiffness and IMCL or EMCL content in 21 overweight and obese men. In the cross-sectional study, EMCL content was positively correlated with baPWV and β-stiffness index, whereas IMCL content was negatively correlated with baPWV. In the intervention study, there were no significant changes in baPWV, β-stiffness index, and IMCL and EMCL contents after aerobic exercise training. However, exercise-induced change in baPWV and β-stiffness index were positively correlated with changes in EMCL content. Moreover, the group of improvements in baPWV was only correlated significantly with reduced EMCL content. These results suggest that IMCL and EMCL contents may affect arterial stiffness in overweight and obese men.
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Affiliation(s)
- Jiyeon Park
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Youngju Choi
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Kanae Myoenzono
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Toru Yoshikawa
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.,Faculty of Health and Sport Sciences, Ryutsu Keizai University, Ibaraki, Japan
| | - Kaname Tagawa
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Tomonori Isobe
- Proton Medical Research Center, University of Tsukuba Hospital, Tsukuba, Ibaraki, Japan
| | - Kousaku Saotome
- Center for Cybernics Research, University of Tsukuba, Ibaraki, Japan
| | - Yoshiyuki Sankai
- Center for Cybernics Research, University of Tsukuba, Ibaraki, Japan
| | - Nobutake Shimojo
- Department of Emergency and Critical Care Medicine, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Seiji Maeda
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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Leon Mercado L, Caron A, Wang Y, Burton M, Gautron L. Identification of Leptin Receptor-Expressing Cells in the Nodose Ganglion of Male Mice. Endocrinology 2019; 160:1307-1322. [PMID: 30907928 PMCID: PMC6482037 DOI: 10.1210/en.2019-00021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/18/2019] [Indexed: 12/29/2022]
Abstract
Leptin has been proposed to modulate viscerosensory information directly at the level of vagal afferents. In support of this view, broad expression for the leptin receptor (Lepr) has previously been reported in vagal afferents. However, the exact identity and distribution of leptin-sensitive vagal afferents has not been elucidated. Using quantitative PCR, we found that the whole mouse nodose ganglion was predominantly enriched in the short form of Lepr, rather than its long form. Consistent with this observation, the acute administration of leptin did not stimulate JAK-STAT signaling in the nodose ganglion. Using chromogenic in situ hybridization in wild-type mice and several reporter mouse models, we demonstrated that Lepr mRNA was restricted to nonneuronal cells in the epineurium and parenchyma of the nodose ganglion and a subset of vagal afferents, which accounted for only 3% of all neuronal profiles. Double labeling studies further established that Lepr-expressing vagal afferents were Nav1.8-negative fibers that did not supply the peritoneal cavity. Finally, double chromogenic in situ hybridization revealed that many Lepr-expressing neurons coexpressed the angiotensin 1a receptor (At1ar), which is a gene expressed in baroreceptors. Taken together, our data challenge the commonly held view that Lepr is broadly expressed in vagal afferents. Instead, our data suggest that leptin may exert a previously unrecognized role, mainly via its short form, as a direct modulator of a very small group of At1ar-positive vagal fibers.
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Affiliation(s)
- Luis Leon Mercado
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Alexandre Caron
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yibing Wang
- Department of Biochemistry, Utah Southwestern Medical Center at Dallas, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Michael Burton
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas
| | - Laurent Gautron
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Correspondence: Laurent Gautron, PhD, Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390. E-mail:
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28
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Minaya DM, Di Lorenzo PM, Hajnal A, Czaja K. Roux‑en‑Y gastric bypass surgery triggers rapid DNA fragmentation in vagal afferent neurons in rats. Acta Neurobiol Exp (Wars) 2019; 79:432-444. [PMID: 31885399 PMCID: PMC7033620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Previous studies have shown that Roux‑en‑Y gastric bypass (RYGB), one of the most effective weight loss treatments for obesity, results in neurodegenerative responses in vagal afferent gut‑brain connection reflected by microglia activation and reduced sensory input to the nucleus tractus solitarius (NTS). However, it is not known whether RYGB‑induced microglia activation is the cause or an effect of the reported neuronal damage. Therefore, the aim of this study was to establish the order of neurodegenerative responses in vagal afferents after RYGB in the nodose ganglia (NG) and NTS in male and female rats. Sprague‑Dawley rats were fed regular chow or an energy‑dense diet for two weeks followed by RYGB or sham surgery. Twenty‑four hours later, animals were sacrificed and NG and NTS were collected. Neuronal cell damage was determined by TUNEL assay. Microglia activation was determined by quantifying the fluorescent staining against the ionizing calcium adapter‑binding molecule 1. Reorganization of vagal afferents was evaluated by fluorescent staining against isolectin 4. Results of the study revealed significantly increased DNA fragmentation in vagal neurons in the NG when observed at 24 h after RYGB. The surgery did not produce rapid changes in the density of vagal afferents and microglia activation in the NTS. These data indicate that decreased density of vagal afferents and increased microglia activation in the NTS likely ensue as a res ult of RYGB‑induced neuronal damage.
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Affiliation(s)
- Dulce M Minaya
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, USA
| | | | - Andras Hajnal
- Department of Neural and Behavioral Sciences, Pennsylvania State University, College of Medicine, Hershey, USA
| | - Krzysztof Czaja
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, USA;
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Cork SC. The role of the vagus nerve in appetite control: Implications for the pathogenesis of obesity. J Neuroendocrinol 2018; 30:e12643. [PMID: 30203877 DOI: 10.1111/jne.12643] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
The communication between the gut and the brain is important for the control of energy homeostasis. In response to food intake, enteroendocrine cells secrete gut hormones, which ultimately suppress appetite through centrally-mediated processes. Increasing evidence implicates the vagus nerve as an important conduit in transmitting these signals from the gastrointestinal tract to the brain. Studies have demonstrated that many of the gut hormones secreted from enteroendocrine cells signal through the vagus nerve, and the sensitivity of the vagus to these signals is regulated by feeding status. Furthermore, evidence suggests that a reduction in the ability of the vagus nerve to respond to the switch between a "fasted" and "fed" state, retaining sensitivity to orexigenic signals when fed or a reduced ability to respond to satiety hormones, may contribute to obesity. This review draws together the evidence that the vagus nerve is a crucial component of appetite regulation via the gut-brain axis, with a particular emphasis on experimental techniques and future developments.
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Affiliation(s)
- Simon C Cork
- Section of Endocrinology and Investigative Medicine, Division of Endocrinology, Diabetes and Metabolism, Imperial College London, London, UK
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30
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Abstract
The regulation of energy and glucose balance contributes to whole-body metabolic homeostasis, and such metabolic regulation is disrupted in obesity and diabetes. Metabolic homeostasis is orchestrated partly in response to nutrient and vagal-dependent gut-initiated functions. Specifically, the sensory and motor fibres of the vagus nerve transmit intestinal signals to the central nervous system and exert biological and physiological responses. In the past decade, the understanding of the regulation of vagal afferent signals and of the associated metabolic effect on whole-body energy and glucose balance has progressed. This Review highlights the contributions made to the understanding of the vagal afferent system and examines the integrative role of the vagal afferent in gastrointestinal regulation of appetite and glucose homeostasis. Investigating the integrative and metabolic role of vagal afferent signalling represents a potential strategy to discover novel therapeutic targets to restore energy and glucose balance in diabetes and obesity.
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Park SJ, Yu Y, Wagner B, Valinsky WC, Lomax AE, Beyak MJ. Increased TASK channel-mediated currents underlie high-fat diet induced vagal afferent dysfunction. Am J Physiol Gastrointest Liver Physiol 2018; 315:G592-G601. [PMID: 29746171 DOI: 10.1152/ajpgi.00335.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously demonstrated that satiety sensing vagal afferent neurons are less responsive to meal-related stimuli in obesity because of reduced electrical excitability. As leak K+ currents are key determinants of membrane excitability, we hypothesized that leak K+ currents are increased in vagal afferents during obesity. Diet-induced obesity was induced by feeding C57Bl/6J mice a high-fat diet (HFF) (60% energy from fat) for 8-10 wk. In vitro extracellular recordings were performed on jejunal afferent nerves. Whole cell patch-clamp recordings were performed on mouse nodose ganglion neurons. Leak K+ currents were isolated using ion substitution and pharmacological blockers. mRNA for TWIK-related acid-sensitive K+ (TASK) subunits was measured using quantitative real-time PCR. Intestinal afferent responses to nutrient (oleate) and non-nutrient (ATP) stimuli were significantly decreased in HFF mice. Voltage clamp experiments revealed the presence of a voltage-insensitive resting potassium conductance that was increased by external alkaline pH and halothane, known properties of TASK currents. In HFF neurons, leak K+ current was approximately doubled and was reduced by TASK1 and TASK3 inhibitors. The halothane sensitive current was similarly increased. Quantitative PCR revealed the presence of mRNA encoding TASK1 (KCNK3) and TASK3 (KCNK9) channels in nodose neurons. TASK3 transcript was significantly increased in HFF mice. The reduction in vagal afferent excitability in obesity is due in part to an increase of resting (leak) K+ conductance. TASK channels may account for the impairment of satiety signaling in diet-induced obesity and thus is a therapeutic target for obesity treatment. NEW & NOTEWORTHY This study characterized the electrophysiological properties and gene expression of the TWIK-related acid-sensitive K+ (TASK) channel in vagal afferent neurons. TASK conductance was increased and contributed to decreased excitability in diet-induced obesity. TASK channels may account for the impairment of satiety signaling in diet-induced obesity and thus is a promising therapeutic target.
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Affiliation(s)
- Sung Jin Park
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Yang Yu
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Brittany Wagner
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - William C Valinsky
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Alan E Lomax
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Michael J Beyak
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
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Li H, Kentish SJ, Wittert GA, Page AJ. Apelin modulates murine gastric vagal afferent mechanosensitivity. Physiol Behav 2018; 194:466-473. [DOI: 10.1016/j.physbeh.2018.06.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/06/2018] [Accepted: 06/27/2018] [Indexed: 12/16/2022]
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Page AJ, Li H. Meal-Sensing Signaling Pathways in Functional Dyspepsia. Front Syst Neurosci 2018; 12:10. [PMID: 29674959 PMCID: PMC5895752 DOI: 10.3389/fnsys.2018.00010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/20/2018] [Indexed: 12/12/2022] Open
Abstract
The upper gastrointestinal tract plays an important role in sensing the arrival, amount and chemical composition of a meal. Ingestion of a meal triggers a number of sensory signals in the gastrointestinal tract. These include the response to mechanical stimulation (e.g., gastric distension), from the presence of food in the gut, and the interaction of various dietary nutrients with specific "taste" receptors on specialized enteroendocrine cells in the small intestine culminating in the release of gut hormones. These signals are then transmitted to the brain where they contribute to food intake regulation by modulating appetite as well as feedback control of gastrointestinal functions (e.g., gut motility). There is evidence that the sensitivity to these food related stimuli is abnormally enhanced in functional dyspepsia leading to symptoms such nausea and bloating. In addition, these gut-brain signals can modulate the signaling pathways involved in visceral pain. This review will discuss the role of gut-brain signals in appetite regulation and the role dysregulation of this system play in functional dyspepsia.
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Affiliation(s)
- Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Hui Li
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
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34
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Silverman HA, Stiegler A, Tsaava T, Newman J, Steinberg BE, Masi EB, Robbiati S, Bouton C, Huerta PT, Chavan SS, Tracey KJ. Standardization of methods to record Vagus nerve activity in mice. Bioelectron Med 2018; 4:3. [PMID: 32232079 PMCID: PMC7098227 DOI: 10.1186/s42234-018-0002-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 02/13/2018] [Indexed: 02/07/2023] Open
Abstract
Background The vagus nerve plays an important role in the regulation of organ function, including reflex pathways that regulate immunity and inflammation. Recent studies using genetically modified mice have improved our understanding of molecular mechanisms in the neural control of immunity. However, mapping neural signals transmitted in the vagus nerve in mice has been limited by technical challenges. Here, we have standardized an experimental protocol to record compound action potentials transmitted in the vagus nerve. Methods The vagus nerve was isolated in Balb/c and B6.129S mice, and placed either on a hook or cuff electrode. The electrical signals from the vagus nerve were digitized using either a Neuralynx or Plexon data acquisition system. Changes in the vagus nerve activity in response to anesthesia, feeding and administration of bacterial endotoxin were analyzed. Results We have developed an electrophysiological recording system to record compound action potentials from the cervical vagus nerve in mice. Cuff electrodes significantly reduce background noise and increase the signal to noise ratio as compared to hook electrodes. Baseline vagus nerve activity varies in response to anesthesia depth and food intake. Analysis of vagus neurograms in different mouse strains (Balb/c and C57BL/6) reveal no significant differences in baseline activity. Importantly, vagus neurogramactivity in wild type and TLR4 receptor knock out mice exhibits receptor dependency of endotoxin mediated signals. Conclusions These methods for recording vagus neurogram in mice provide a useful tool to further delineate the role of vagus neural pathways in a standardized murine disease model.
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Affiliation(s)
- Harold A Silverman
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA.,Hofstra Northwell Health School of Medicine, 350 Community Drive, Manhasset, NY 11030 USA
| | - Andrew Stiegler
- Circulatory Technologies, Inc., 350 Community Drive, Manhasset, NY 11030 USA
| | - Téa Tsaava
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Justin Newman
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Benjamin E Steinberg
- 4Department of Anesthesia, University of Toronto, 150 College Street, Toronto, ON M5S 3E2 Canada
| | - Emily Battinelli Masi
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA.,Hofstra Northwell Health School of Medicine, 350 Community Drive, Manhasset, NY 11030 USA
| | - Sergio Robbiati
- 5Laboratory of Immune & Neural Networks, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Chad Bouton
- 6Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Patricio T Huerta
- 5Laboratory of Immune & Neural Networks, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Sangeeta S Chavan
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA.,Hofstra Northwell Health School of Medicine, 350 Community Drive, Manhasset, NY 11030 USA.,6Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
| | - Kevin J Tracey
- 1Center for Biomedical Sciences, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA.,Hofstra Northwell Health School of Medicine, 350 Community Drive, Manhasset, NY 11030 USA.,6Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY 11030 USA
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Trancikova A, Kovacova E, Ru F, Varga K, Brozmanova M, Tatar M, Kollarik M. Distinct Expression of Phenotypic Markers in Placodes- and Neural Crest-Derived Afferent Neurons Innervating the Rat Stomach. Dig Dis Sci 2018; 63:383-394. [PMID: 29275446 DOI: 10.1007/s10620-017-4883-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 12/12/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Visceral pain is initiated by activation of primary afferent neurons among which the capsaicin-sensitive (TRPV1-positive) neurons play an important role. The stomach is a common source of visceral pain. Similar to other organs, the stomach receives dual spinal and vagal afferent innervation. Developmentally, spinal dorsal root ganglia (DRG) and vagal jugular neurons originate from embryonic neural crest and vagal nodose neurons originate from placodes. In thoracic organs the neural crest- and placodes-derived TRPV1-positive neurons have distinct phenotypes differing in activation profile, neurotrophic regulation and reflex responses. It is unknown to whether such distinction exists in the stomach. AIMS We hypothesized that gastric neural crest- and placodes-derived TRPV1-positive neurons express phenotypic markers indicative of placodes and neural crest phenotypes. METHODS Gastric DRG and vagal neurons were retrogradely traced by DiI injected into the rat stomach wall. Single-cell RT-PCR was performed on traced gastric neurons. RESULTS Retrograde tracing demonstrated that vagal gastric neurons locate exclusively into the nodose portion of the rat jugular/petrosal/nodose complex. Gastric DRG TRPV1-positive neurons preferentially expressed markers PPT-A, TrkA and GFRα3 typical for neural crest-derived TRPV1-positive visceral neurons. In contrast, gastric nodose TRPV1-positive neurons preferentially expressed markers P2X2 and TrkB typical for placodes-derived TRPV1-positive visceral neurons. Differential expression of neural crest and placodes markers was less pronounced in TRPV1-negative DRG and nodose populations. CONCLUSIONS There are phenotypic distinctions between the neural crest-derived DRG and placodes-derived vagal nodose TRPV1-positive neurons innervating the rat stomach that are similar to those described in thoracic organs.
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Affiliation(s)
- Alzbeta Trancikova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Eva Kovacova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Fei Ru
- Department of Medicine, The Johns Hopkins University School of Medicine, Johns Hopkins Asthma Center, RM 1A.2, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA
| | - Kristian Varga
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Mariana Brozmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Milos Tatar
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Biomedical Center Martin JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin (JFM CU), Department of Pathophysiology JFM CU, Malá Hora 4C, 036 01, Martin, Slovakia
| | - Marian Kollarik
- Department of Medicine, The Johns Hopkins University School of Medicine, Johns Hopkins Asthma Center, RM 1A.2, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA.
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36
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Li H, Kentish SJ, Wittert GA, Page AJ. The role of neuropeptide W in energy homeostasis. Acta Physiol (Oxf) 2018; 222. [PMID: 28376284 DOI: 10.1111/apha.12884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 12/05/2016] [Accepted: 03/28/2017] [Indexed: 12/14/2022]
Abstract
Neuropeptide W is the endogenous ligand for G-protein-coupled receptors GPR7 and GPR8. In this review, we summarize findings on the distribution of neuropeptide W and its receptors in the central nervous system and the periphery, and discuss the role of NPW in food intake and energy homeostasis.
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Affiliation(s)
- H. Li
- Vagal Afferent Research Group; Centre for Nutrition and Gastrointestinal Diseases; Adelaide Medical School; University of Adelaide; Adelaide SA Australia
- South Australian Health and Medical Research Institute (SAHMRI); Adelaide SA Australia
| | - S. J. Kentish
- Vagal Afferent Research Group; Centre for Nutrition and Gastrointestinal Diseases; Adelaide Medical School; University of Adelaide; Adelaide SA Australia
- South Australian Health and Medical Research Institute (SAHMRI); Adelaide SA Australia
| | - G. A. Wittert
- Vagal Afferent Research Group; Centre for Nutrition and Gastrointestinal Diseases; Adelaide Medical School; University of Adelaide; Adelaide SA Australia
- South Australian Health and Medical Research Institute (SAHMRI); Adelaide SA Australia
- Royal Adelaide Hospital; Adelaide SA Australia
| | - A. J. Page
- Vagal Afferent Research Group; Centre for Nutrition and Gastrointestinal Diseases; Adelaide Medical School; University of Adelaide; Adelaide SA Australia
- South Australian Health and Medical Research Institute (SAHMRI); Adelaide SA Australia
- Royal Adelaide Hospital; Adelaide SA Australia
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Christie S, Wittert GA, Li H, Page AJ. Involvement of TRPV1 Channels in Energy Homeostasis. Front Endocrinol (Lausanne) 2018; 9:420. [PMID: 30108548 PMCID: PMC6079260 DOI: 10.3389/fendo.2018.00420] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/04/2018] [Indexed: 12/25/2022] Open
Abstract
The ion channel TRPV1 is involved in a wide range of processes including nociception, thermosensation and, more recently discovered, energy homeostasis. Tightly controlling energy homeostasis is important to maintain a healthy body weight, or to aid in weight loss by expending more energy than energy intake. TRPV1 may be involved in energy homeostasis, both in the control of food intake and energy expenditure. In the periphery, it is possible that TRPV1 can impact on appetite through control of appetite hormone levels or via modulation of gastrointestinal vagal afferent signaling. Further, TRPV1 may increase energy expenditure via heat production. Dietary supplementation with TRPV1 agonists, such as capsaicin, has yielded conflicting results with some studies indicating a reduction in food intake and increase in energy expenditure, and other studies indicating the converse. Nonetheless, it is increasingly apparent that TRPV1 may be dysregulated in obesity and contributing to the development of this disease. The mechanisms behind this dysregulation are currently unknown but interactions with other systems, such as the endocannabinoid systems, could be altered and therefore play a role in this dysregulation. Further, TRPV1 channels appear to be involved in pancreatic insulin secretion. Therefore, given its plausible involvement in regulation of energy and glucose homeostasis and its dysregulation in obesity, TRPV1 may be a target for weight loss therapy and diabetes. However, further research is required too fully elucidate TRPV1s role in these processes. The review provides an overview of current knowledge in this field and potential areas for development.
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Affiliation(s)
- Stewart Christie
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Gary A. Wittert
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Hui Li
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Amanda J. Page
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- *Correspondence: Amanda J. Page
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Breit S, Kupferberg A, Rogler G, Hasler G. Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders. Front Psychiatry 2018; 9:44. [PMID: 29593576 PMCID: PMC5859128 DOI: 10.3389/fpsyt.2018.00044] [Citation(s) in RCA: 473] [Impact Index Per Article: 78.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 02/01/2018] [Indexed: 12/13/2022] Open
Abstract
The vagus nerve represents the main component of the parasympathetic nervous system, which oversees a vast array of crucial bodily functions, including control of mood, immune response, digestion, and heart rate. It establishes one of the connections between the brain and the gastrointestinal tract and sends information about the state of the inner organs to the brain via afferent fibers. In this review article, we discuss various functions of the vagus nerve which make it an attractive target in treating psychiatric and gastrointestinal disorders. There is preliminary evidence that vagus nerve stimulation is a promising add-on treatment for treatment-refractory depression, posttraumatic stress disorder, and inflammatory bowel disease. Treatments that target the vagus nerve increase the vagal tone and inhibit cytokine production. Both are important mechanism of resiliency. The stimulation of vagal afferent fibers in the gut influences monoaminergic brain systems in the brain stem that play crucial roles in major psychiatric conditions, such as mood and anxiety disorders. In line, there is preliminary evidence for gut bacteria to have beneficial effect on mood and anxiety, partly by affecting the activity of the vagus nerve. Since, the vagal tone is correlated with capacity to regulate stress responses and can be influenced by breathing, its increase through meditation and yoga likely contribute to resilience and the mitigation of mood and anxiety symptoms.
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Affiliation(s)
- Sigrid Breit
- Division of Molecular Psychiatry, Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Aleksandra Kupferberg
- Division of Molecular Psychiatry, Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Gerhard Rogler
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Gregor Hasler
- Division of Molecular Psychiatry, Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
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Diepenbroek C, Quinn D, Stephens R, Zollinger B, Anderson S, Pan A, de Lartigue G. Validation and characterization of a novel method for selective vagal deafferentation of the gut. Am J Physiol Gastrointest Liver Physiol 2017; 313:G342-G352. [PMID: 28705805 PMCID: PMC5668568 DOI: 10.1152/ajpgi.00095.2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/01/2017] [Accepted: 06/23/2017] [Indexed: 01/31/2023]
Abstract
There is a lack of tools that selectively target vagal afferent neurons (VAN) innervating the gut. We use saporin (SAP), a potent neurotoxin, conjugated to the gastronintestinal (GI) hormone cholecystokinin (CCK-SAP) injected into the nodose ganglia (NG) of male Wistar rats to specifically ablate GI-VAN. We report that CCK-SAP ablates a subpopulation of VAN in culture. In vivo, CCK-SAP injection into the NG reduces VAN innervating the mucosal and muscular layers of the stomach and small intestine but not the colon, while leaving vagal efferent neurons intact. CCK-SAP abolishes feeding-induced c-Fos in the NTS, as well as satiation by CCK or glucagon like peptide-1 (GLP-1). CCK-SAP in the NG of mice also abolishes CCK-induced satiation. Therefore, we provide multiple lines of evidence that injection of CCK-SAP in NG is a novel selective vagal deafferentation technique of the upper GI tract that works in multiple vertebrate models. This method provides improved tissue specificity and superior separation of afferent and efferent signaling compared with vagotomy, capsaicin, and subdiaphragmatic deafferentation.NEW & NOTEWORTHY We develop a new method that allows targeted lesioning of vagal afferent neurons that innervate the upper GI tract while sparing vagal efferent neurons. This reliable approach provides superior tissue specificity and selectivity for vagal afferent over efferent targeting than traditional approaches. It can be used to address questions about the role of gut to brain signaling in physiological and pathophysiological conditions.
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Affiliation(s)
- Charlene Diepenbroek
- The John B. Pierce Laboratory, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale Medical School, New Haven, Connecticut; and
| | | | - Ricky Stephens
- Department of Anatomy, Physiology, and Cell Biology, University of California Davis, Davis, California
| | | | - Seth Anderson
- The John B. Pierce Laboratory, New Haven, Connecticut
| | - Annabelle Pan
- The John B. Pierce Laboratory, New Haven, Connecticut
| | - Guillaume de Lartigue
- The John B. Pierce Laboratory, New Haven, Connecticut;
- Department of Cellular and Molecular Physiology, Yale Medical School, New Haven, Connecticut; and
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Monteiro MP, Batterham RL. The Importance of the Gastrointestinal Tract in Controlling Food Intake and Regulating Energy Balance. Gastroenterology 2017; 152:1707-1717.e2. [PMID: 28193513 DOI: 10.1053/j.gastro.2017.01.053] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/31/2016] [Accepted: 01/03/2017] [Indexed: 12/16/2022]
Abstract
The gastrointestinal tract, the key interface between ingested nutrients and the body, plays a critical role in regulating energy homeostasis. Gut-derived signals convey information regarding incoming nutrients to the brain, initiating changes in eating behavior and energy expenditure, to maintain energy balance. Here we review hormonal, neural, and nutrient signals emanating from the gastrointestinal tract and evidence for their role in controlling feeding behavior. Mechanistic studies that have utilized pharmacologic and/or transgenic approaches targeting an individual hormone/mediator have yielded somewhat disappointing body weight changes, often leading to the hormone/mediator in question being dismissed as a potential obesity therapy. However, the recent finding of sustained weight reduction in response to systemic administration of a long-acting analog of the gut-hormone glucagon-like peptide-1 highlights the therapeutic potential of gut-derived signals acting via nonphysiologic mechanisms. Thus, we also review therapeutics strategies being utilized or developed to leverage gastrointestinal signals in order to treat obesity.
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Affiliation(s)
- Mariana P Monteiro
- Clinical and Experimental Endocrinology, Unit for Multidisciplinary Research in Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Portugal; Centre for Obesity Research, University College London, London, United Kingdom; University College London Hospitals Bariatric Centre for Weight Management and Metabolic Surgery, London, United Kingdom
| | - Rachel L Batterham
- Centre for Obesity Research, University College London, London, United Kingdom; University College London Hospitals Bariatric Centre for Weight Management and Metabolic Surgery, London, United Kingdom; National Institute of Health Research University College London Hospitals Biomedical Research Centre, London, United Kingdom.
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Page AJ, Kentish SJ. Plasticity of gastrointestinal vagal afferent satiety signals. Neurogastroenterol Motil 2017; 29. [PMID: 27781333 DOI: 10.1111/nmo.12973] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
The vagal link between the gastrointestinal tract and the central nervous system (CNS) has numerous vital functions for maintaining homeostasis. The regulation of energy balance is one which is attracting more and more attention due to the potential for exploiting peripheral hormonal targets as treatments for conditions such as obesity. While physiologically, this system is well tuned and demonstrated to be effective in the regulation of both local function and promoting/terminating food intake the neural connection represents a susceptible pathway for disruption in various disease states. Numerous studies have revealed that obesity in particularly is associated with an array of modifications in vagal afferent function from changes in expression of signaling molecules to altered activation mechanics. In general, these changes in vagal afferent function in obesity further promote food intake instead of the more desirable reduction in food intake. It is essential to gain a comprehensive understanding of the mechanisms responsible for these detrimental effects before we can establish more effective pharmacotherapies or lifestyle strategies for the treatment of obesity and the maintenance of weight loss.
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Affiliation(s)
- A J Page
- Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia.,Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.,Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - S J Kentish
- Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia.,Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.,School of Medicine, University of Queensland, St Lucia, QLD, Australia
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Clarifying the Ghrelin System's Ability to Regulate Feeding Behaviours Despite Enigmatic Spatial Separation of the GHSR and Its Endogenous Ligand. Int J Mol Sci 2017; 18:ijms18040859. [PMID: 28422060 PMCID: PMC5412441 DOI: 10.3390/ijms18040859] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/04/2017] [Accepted: 04/11/2017] [Indexed: 12/23/2022] Open
Abstract
Ghrelin is a hormone predominantly produced in and secreted from the stomach. Ghrelin is involved in many physiological processes including feeding, the stress response, and in modulating learning, memory and motivational processes. Ghrelin does this by binding to its receptor, the growth hormone secretagogue receptor (GHSR), a receptor found in relatively high concentrations in hypothalamic and mesolimbic brain regions. While the feeding and metabolic effects of ghrelin can be explained by the effects of this hormone on regions of the brain that have a more permeable blood brain barrier (BBB), ghrelin produced within the periphery demonstrates a limited ability to reach extrahypothalamic regions where GHSRs are expressed. Therefore, one of the most pressing unanswered questions plaguing ghrelin research is how GHSRs, distributed in brain regions protected by the BBB, are activated despite ghrelin’s predominant peripheral production and poor ability to transverse the BBB. This manuscript will describe how peripheral ghrelin activates central GHSRs to encourage feeding, and how central ghrelin synthesis and ghrelin independent activation of GHSRs may also contribute to the modulation of feeding behaviours.
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Grabauskas G, Owyang C. Plasticity of vagal afferent signaling in the gut. MEDICINA-LITHUANIA 2017; 53:73-84. [PMID: 28454890 PMCID: PMC6318799 DOI: 10.1016/j.medici.2017.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 03/21/2017] [Indexed: 12/13/2022]
Abstract
Vagal sensory neurons mediate the vago-vagal reflex which, in turn, regulates a wide array of gastrointestinal functions including esophageal motility, gastric accommodation and pancreatic enzyme secretion. These neurons also transmit sensory information from the gut to the central nervous system, which then mediates the sensations of nausea, fullness and satiety. Recent research indicates that vagal afferent neurons process non-uniform properties and a significant degree of plasticity. These properties are important to ensure that vagally regulated gastrointestinal functions respond rapidly and appropriately to various intrinsic and extrinsic factors. Similar plastic changes in the vagus also occur in pathophysiological conditions, such as obesity and diabetes, resulting in abnormal gastrointestinal functions. A clear understanding of the mechanisms which mediate these events may provide novel therapeutic targets for the treatment of gastrointestinal disorders due to vago-vagal pathway malfunctions.
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Affiliation(s)
- Gintautas Grabauskas
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48019, USA.
| | - Chung Owyang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48019, USA
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Huizinga JD. Commentary: Phase-amplitude coupling at the organism level: The amplitude of spontaneous alpha rhythm fluctuations varies with the phase of the infra-slow gastric basal rhythm. Front Neurosci 2017; 11:102. [PMID: 28303088 PMCID: PMC5332408 DOI: 10.3389/fnins.2017.00102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 02/17/2017] [Indexed: 01/09/2023] Open
Affiliation(s)
- Jan D Huizinga
- Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University Hamilton, ON, Canada
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Kentish SJ, Li H, Frisby CL, Page AJ. Nesfatin-1 modulates murine gastric vagal afferent mechanosensitivity in a nutritional state dependent manner. Peptides 2017; 89:35-41. [PMID: 28087413 DOI: 10.1016/j.peptides.2017.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 02/07/2023]
Abstract
Food intake is regulated by vagal afferent signals from the stomach. Nesfatin-1 is an anorexigenic peptide produced within the gastrointestinal tract and has well defined central effects. We aimed to determine if nesfatin-1 can modulate gastric vagal afferent signals in the periphery and further whether this is altered in different nutritional states. Female C57BL/6J mice were fed either a standard laboratory diet (SLD) or a high fat diet (HFD) for 12 weeks or fasted overnight. Plasma nucleobindin-2 (NUCB2; nesfatin-1 precursor)/nesfatin-1 levels were assayed, the expression of NUCB2 in the gastric mucosa and adipose tissue was assessed using real-time quantitative reverse-transcription polymerase chain reaction. An in vitro preparation was used to determine the effect of nesfatin-1 on gastric vagal afferent mechanosensitivity. HFD mice exhibited an increased body weight and adiposity. Plasma NUCB2/nesfatin-1 levels were unchanged between any of the groups of mice. NUCB2 mRNA was detected in the gastric mucosa and gonadal fat of SLD, HFD and fasted mice with no difference in mRNA abundance between groups in either tissue. In SLD and fasted mice nesfatin-1 potentiated mucosal receptor mechanosensitivity, an effect not observed in HFD mice. Tension receptor mechanosensitivity was unaffected by nesfatin-1 in SLD and fasted mice, but was inhibited in HFD mice. In conclusion, Nesfatin-1 modulates gastric vagal afferent mechanosensitivity in a nutritional state dependent manner.
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Affiliation(s)
- Stephen J Kentish
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Frome Road, Adelaide, SA 5005, Australia; Nutrition and Metabolism, South Australian Health and Medical Research Institute, North Terrace, SA 5000, Australia; School of Medicine, University of Queensland, St Lucia, QLD 4067, Australia
| | - Hui Li
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Frome Road, Adelaide, SA 5005, Australia; Nutrition and Metabolism, South Australian Health and Medical Research Institute, North Terrace, SA 5000, Australia
| | - Claudine L Frisby
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Frome Road, Adelaide, SA 5005, Australia; Nutrition and Metabolism, South Australian Health and Medical Research Institute, North Terrace, SA 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Frome Road, Adelaide, SA 5005, Australia; Nutrition and Metabolism, South Australian Health and Medical Research Institute, North Terrace, SA 5000, Australia; Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia.
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Browning KN, Verheijden S, Boeckxstaens GE. The Vagus Nerve in Appetite Regulation, Mood, and Intestinal Inflammation. Gastroenterology 2017; 152:730-744. [PMID: 27988382 PMCID: PMC5337130 DOI: 10.1053/j.gastro.2016.10.046] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/27/2016] [Accepted: 10/27/2016] [Indexed: 02/07/2023]
Abstract
Although the gastrointestinal tract contains intrinsic neural plexuses that allow a significant degree of independent control over gastrointestinal functions, the central nervous system provides extrinsic neural inputs that modulate, regulate, and integrate these functions. In particular, the vagus nerve provides the parasympathetic innervation to the gastrointestinal tract, coordinating the complex interactions between central and peripheral neural control mechanisms. This review discusses the physiological roles of the afferent (sensory) and motor (efferent) vagus in regulation of appetite, mood, and the immune system, as well as the pathophysiological outcomes of vagus nerve dysfunction resulting in obesity, mood disorders, and inflammation. The therapeutic potential of vagus nerve modulation to attenuate or reverse these pathophysiological outcomes and restore autonomic homeostasis is also discussed.
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Affiliation(s)
- Kirsteen N. Browning
- Department of Neural and Behavioral Science Penn State College of Medicine 500 University Drive MC H109 Hershey, PA 17033
| | - Simon Verheijden
- Translational Research Center of Gastrointestinal Disorders (TARGID) KU Leuven Herestraat 49 3000 Leuven, Belgium
| | - Guy E. Boeckxstaens
- Translational Research Center of Gastrointestinal Disorders (TARGID) KU Leuven Herestraat 49 3000 Leuven, Belgium,Division of Gastroenterology & Hepatology University Hospital Leuven Herestraat 49 3000 Leuven, Belgium,Address of correspondence: Prof. dr. Guy Boeckxstaens,
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Campaniello MA, Mavrangelos C, Eade S, Harrington AM, Blackshaw LA, Brierley SM, Smid SD, Hughes PA. Acute colitis chronically alters immune infiltration mechanisms and sensory neuro-immune interactions. Brain Behav Immun 2017; 60:319-332. [PMID: 27864046 DOI: 10.1016/j.bbi.2016.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/07/2016] [Accepted: 11/15/2016] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE Little is understood regarding how disease progression alters immune and sensory nerve function in colitis. We investigated how acute colitis chronically alters immune recruitment and the impact this has on re-activated colitis. To understand the impact of disease progress on sensory systems we investigated the mechanisms underlying altered colonic neuro-immune interactions after acute colitis. DESIGN Inflammation was compared in mouse models of health, acute tri-nitrobenzene sulphonic acid (TNBS) colitis, Remission and Reactivated colitis. Cytokine concentrations were compared by ELISA in-situ and in explanted colon tissue. Colonic infiltration by CD11b/F4-80 macrophage, CD4 THELPER (TH) and CD8 TCYTOTOXIC (TC) and α4β7 expression on mesenteric lymph node (MLN) TH and TC was determined by flow cytometry. Cytokine and effector receptor mRNA expression was determined on colo-rectal afferent neurons and the mechanisms underlying cytokinergic effects on high-threshold colo-rectal afferent function were investigated using electrophysiology. RESULTS Colonic damage, MPO activity, macrophage infiltration, IL-1β and IL-6 concentrations were lower in Reactivated compared to Acute colitis. TH infiltration and α4β7 expression on TH MLN was increased in Remission but not Acute colitis. IFN-γ concentrations, TH infiltration and α4β7 expression on TH and TC MLN increased in Reactivated compared to Acute colitis. Reactivated explants secreted more IL-1β and IL-6 than Acute explants. IL-6 and TNF-α inhibited colo-rectal afferent mechanosensitivity in Remission mice via a BKCa dependent mechanism. CONCLUSIONS Acute colitis persistently alters immune responses and afferent nerve signalling pathways to successive episodes of colitis. These findings highlight the complexity of viscero-sensory neuro-immune interactions in painful remitting and relapsing diseases.
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Affiliation(s)
- Melissa A Campaniello
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Chris Mavrangelos
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Samuel Eade
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia; Department of Pharmacology, University of Adelaide, Adelaide, Australia
| | - Andrea M Harrington
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - L Ashley Blackshaw
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, UK
| | - Stuart M Brierley
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Scott D Smid
- Department of Pharmacology, University of Adelaide, Adelaide, Australia
| | - Patrick A Hughes
- Centre for Nutrition and Gastrointestinal Diseases, University of Adelaide and South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia.
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Takada M, Nishida K, Kataoka-Kato A, Gondo Y, Ishikawa H, Suda K, Kawai M, Hoshi R, Watanabe O, Igarashi T, Kuwano Y, Miyazaki K, Rokutan K. Probiotic Lactobacillus casei strain Shirota relieves stress-associated symptoms by modulating the gut-brain interaction in human and animal models. Neurogastroenterol Motil 2016; 28:1027-36. [PMID: 26896291 DOI: 10.1111/nmo.12804] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/24/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND This study aimed to examine the effects of Lactobacillus casei strain Shirota (LcS) on gut-brain interactions under stressful conditions. METHODS Three double-blind, placebo-controlled trials were conducted to examine the effects of LcS on psychological and physiological stress responses in healthy medical students under academic examination stress. Subjects received LcS-fermented milk or placebo daily for 8 weeks prior to taking a national standardized examination. Subjective anxiety scores, salivary cortisol levels, and the presence of physical symptoms during the intervention were pooled and analyzed. In the animal study, rats were given feed with or without LcS for 2 weeks, then submitted to water avoidance stress (WAS). Plasma corticosterone concentration and the expression of cFos and corticotropin releasing factor (CRF) in the paraventricular nucleus (PVN) were measured immediately after WAS. In an electrophysiological study, gastric vagal afferent nerve activity was monitored after intragastric administration of LcS to urethane-anesthetized rats. KEY RESULTS Academic stress-induced increases in salivary cortisol levels and the incidence rate of physical symptoms were significantly suppressed in the LcS group compared with the placebo group. In rats pretreated with LcS, WAS-induced increases in plasma corticosterone were significantly suppressed, and the number of CRF-expressing cells in the PVN was reduced. Intragastric administration of LcS stimulated gastric vagal afferent activity in a dose-dependent manner. CONCLUSIONS & INFERENCES These findings suggest that LcS may prevent hypersecretion of cortisol and physical symptoms under stressful conditions, possibly through vagal afferent signaling to the brain and reduced stress reactivity in the PVN.
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Affiliation(s)
- M Takada
- Yakult Central Institute, Tokyo, Japan
| | - K Nishida
- Department of Pathophysiology, Tokushima University Graduate School of Medicine, Tokushima, Japan
| | | | - Y Gondo
- Yakult Central Institute, Tokyo, Japan
| | | | - K Suda
- Yakult Central Institute, Tokyo, Japan
| | - M Kawai
- Yakult Central Institute, Tokyo, Japan
| | - R Hoshi
- Faculty of Research and Development, Yakult Honsha Co., Ltd., Tokyo, Japan
| | - O Watanabe
- Faculty of Research and Development, Yakult Honsha Co., Ltd., Tokyo, Japan
| | - T Igarashi
- Faculty of Research and Development, Yakult Honsha Co., Ltd., Tokyo, Japan
| | - Y Kuwano
- Department of Pathophysiology, Tokushima University Graduate School of Medicine, Tokushima, Japan
| | | | - K Rokutan
- Department of Pathophysiology, Tokushima University Graduate School of Medicine, Tokushima, Japan
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de Lartigue G. Role of the vagus nerve in the development and treatment of diet-induced obesity. J Physiol 2016; 594:5791-5815. [PMID: 26959077 DOI: 10.1113/jp271538] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/26/2016] [Indexed: 12/21/2022] Open
Abstract
This review highlights evidence for a role of the vagus nerve in the development of obesity and how targeting the vagus nerve with neuromodulation or pharmacology can be used as a therapeutic treatment of obesity. The vagus nerve innervating the gut plays an important role in controlling metabolism. It communicates peripheral information about the volume and type of nutrients between the gut and the brain. Depending on the nutritional status, vagal afferent neurons express two different neurochemical phenotypes that can inhibit or stimulate food intake. Chronic ingestion of calorie-rich diets reduces sensitivity of vagal afferent neurons to peripheral signals and their constitutive expression of orexigenic receptors and neuropeptides. This disruption of vagal afferent signalling is sufficient to drive hyperphagia and obesity. Furthermore neuromodulation of the vagus nerve can be used in the treatment of obesity. Although the mechanisms are poorly understood, vagal nerve stimulation prevents weight gain in response to a high-fat diet. In small clinical studies, in patients with depression or epilepsy, vagal nerve stimulation has been demonstrated to promote weight loss. Vagal blockade, which inhibits the vagus nerve, results in significant weight loss. Vagal blockade is proposed to inhibit aberrant orexigenic signals arising in obesity as a putative mechanism of vagal blockade-induced weight loss. Approaches and molecular targets to develop future pharmacotherapy targeted to the vagus nerve for the treatment of obesity are proposed. In conclusion there is strong evidence that the vagus nerve is involved in the development of obesity and it is proving to be an attractive target for the treatment of obesity.
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Affiliation(s)
- Guillaume de Lartigue
- The John B. Pierce Laboratory, New Haven, CT, USA. .,Dept Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
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Page AJ. Mimecan: A Newly Identified Adipokine and Regulator of Appetite. EBioMedicine 2016; 2:1584-5. [PMID: 26870776 PMCID: PMC4740335 DOI: 10.1016/j.ebiom.2015.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 11/03/2015] [Accepted: 11/03/2015] [Indexed: 11/29/2022] Open
Affiliation(s)
- Amanda J Page
- Centre for Nutrition and Gastrointestinal Disease, Discipline of Medicine, University of Adelaide, Frome Road, Adelaide, SA 5005, Australia
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