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Wachsmuth HR, Weninger SN, Duca FA. Role of the gut-brain axis in energy and glucose metabolism. Exp Mol Med 2022; 54:377-392. [PMID: 35474341 PMCID: PMC9076644 DOI: 10.1038/s12276-021-00677-w] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/01/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal tract plays a role in the development and treatment of metabolic diseases. During a meal, the gut provides crucial information to the brain regarding incoming nutrients to allow proper maintenance of energy and glucose homeostasis. This gut-brain communication is regulated by various peptides or hormones that are secreted from the gut in response to nutrients; these signaling molecules can enter the circulation and act directly on the brain, or they can act indirectly via paracrine action on local vagal and spinal afferent neurons that innervate the gut. In addition, the enteric nervous system can act as a relay from the gut to the brain. The current review will outline the different gut-brain signaling mechanisms that contribute to metabolic homeostasis, highlighting the recent advances in understanding these complex hormonal and neural pathways. Furthermore, the impact of the gut microbiota on various components of the gut-brain axis that regulates energy and glucose homeostasis will be discussed. A better understanding of the gut-brain axis and its complex relationship with the gut microbiome is crucial for the development of successful pharmacological therapies to combat obesity and diabetes.
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Affiliation(s)
| | | | - Frank A Duca
- School of Animal and Comparative Biomedical Sciences, College of Agricultural and Life Sciences, University of Arizona, Tucson, AZ, USA. .,BIO5, University of Arizona, Tucson, AZ, USA.
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2
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Kovacs P, Hajnal A. Short-term high-fat diet consumption increases body weight and body adiposity and alters brain stem taste information processing in rats. Chem Senses 2022; 47:6673811. [PMID: 35997757 DOI: 10.1093/chemse/bjac020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Diet-induced obesity is known to develop whether exposed to a high-energy diet (HED) or a high-fat diet (HFD). However, it is still not clear whether the elevated energy content or the macronutrient imbalance is the key factor in early disease progression. Therefore, this study compared the short-term effects of 2 widely used rodent obesogenic diets, an HFD with 60 kcal% fat content and a carbohydrate-based HED, on the body weight, body fat content, glucose tolerance, and neuronal taste responses in rats. We found that only HFD induced an early significant body weight increase compared with the control normal diet (ND) group, starting on week 4, and resulting in a significantly elevated body adiposity compared with both the ND and HED groups. Oral glucose tolerance test revealed no difference across groups. Subsequently, we also found that HFD resulted in a significant body weight gain even under energy-restricted (isocaloric to ND) conditions. In vivo electrophysiological recordings revealed that only the ad libitum HFD and not the isocaloric-HFD altered the brain stem gustatory neural responses to oral taste stimulation. In conclusion, this study showed that increased fat intake might result in significant body weight gain even under isocaloric and metabolically healthy conditions and demonstrated changes in central taste processing in an early stage of dietary obesity. A better understanding of these initial physiological changes may offer new drug targets for preventing obesity.
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Affiliation(s)
- Peter Kovacs
- Department of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Andras Hajnal
- Department of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State University, Hershey, PA 17033, USA
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3
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Steenackers N, Wauters L, Van der Schueren B, Augustijns P, Falony G, Koziolek M, Lannoo M, Mertens A, Meulemans A, Raes J, Vangoitsenhoven R, Vieira-Silva S, Weitschies W, Matthys C, Vanuytsel T. Effect of obesity on gastrointestinal transit, pressure and pH using a wireless motility capsule. Eur J Pharm Biopharm 2021; 167:1-8. [PMID: 34273543 DOI: 10.1016/j.ejpb.2021.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/22/2021] [Accepted: 07/07/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Despite the increasing prevalence and medical burden of obesity, the understanding of gastrointestinal physiology in obesity is scarce, which hampers drug development. AIM To investigate the effect of obesity and food intake on gastrointestinal transit, pressure and pH. MATERIAL AND METHODS An exploratory cross-sectional study using a wireless motility capsule (SmartPill©) was performed in 11 participants with obesity and 11 age- and gender-matched participants with normal weight (group) in fasted and fed state (visit). During the first visit, the capsule was ingested after an overnight fast. During a second visit, the capsule was ingested after a nutritional drink to simulate fed state. Linear mixed models were constructed to compare segmental gastrointestinal transit, pressure and pH between groups (obesity or control) and within every group (fasted or fed). RESULTS Food intake slowed gastric emptying in both groups (both P < 0.0001), though food-induced gastric contractility was higher in participants with obesity compared to controls (P = 0.02). In the small intestine, a higher contractility (P = 0.001), shorter transit (P = 0.04) and lower median pH (P = 0.002) was observed in participants with obesity compared to controls. No differences were observed for colonic measurements. CONCLUSION Obesity has a profound impact on gastrointestinal physiology, which should be taken into account for drug development.
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Affiliation(s)
- N Steenackers
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium.
| | - L Wauters
- Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium.
| | - B Van der Schueren
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - P Augustijns
- Drug Delivery and Disposition, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| | - G Falony
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - M Koziolek
- Institute of Pharmacy, Center of Drug Absorption and Transport, University of Greifswald, Greifswald, Germany.
| | - M Lannoo
- Department of Abdominal Surgery, University Hospitals Leuven, Leuven, Belgium.
| | - A Mertens
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - A Meulemans
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - J Raes
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - R Vangoitsenhoven
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - S Vieira-Silva
- Rega Institute, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium; Center for Microbiology, VIB, Leuven, Belgium.
| | - W Weitschies
- Institute of Pharmacy, Center of Drug Absorption and Transport, University of Greifswald, Greifswald, Germany.
| | - C Matthys
- Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
| | - T Vanuytsel
- Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium; Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium.
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4
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Cristina Oliveira de Lima V, Piuvezam G, Leal Lima Maciel B, Heloneida de Araújo Morais A. Trypsin inhibitors: promising candidate satietogenic proteins as complementary treatment for obesity and metabolic disorders? J Enzyme Inhib Med Chem 2019; 34:405-419. [PMID: 30734596 PMCID: PMC6327991 DOI: 10.1080/14756366.2018.1542387] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/16/2018] [Accepted: 10/26/2018] [Indexed: 10/27/2022] Open
Abstract
The increase in non-communicable chronic diseases has aroused interest in the research of adjuvants to the classic forms of treatments. Obesity and metabolic syndrome are the main targets of confrontation because they relate directly to other chronic diseases. In this context, trypsin inhibitors, molecules with wide heterologous application, appear as possibilities in the treatment of overweight and obesity due to the action on satiety related mechanisms, mainly in the modulation of satiety hormones, such as cholecystokinin. In addition, trypsin inhibitors have the ability to also act on some biochemical parameters related to these diseases, thus, emerging as potential candidates and promising molecules in the treatment of the obesity and metabolic syndrome. Thus, the present article proposes to approach, through a systematic literature review, the advantages, disadvantages and viabilities for the use of trypsin inhibitors directed to the treatment of overweight and obesity.
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Affiliation(s)
| | - Grasiela Piuvezam
- Department of Collective Health, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Bruna Leal Lima Maciel
- Department of Nutrition, Center for Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Ana Heloneida de Araújo Morais
- Department of Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Brazil
- Department of Nutrition, Center for Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil
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5
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Grabauskas G, Wu X, Zhou S, Li J, Gao J, Owyang C. High-fat diet-induced vagal afferent dysfunction via upregulation of 2-pore domain potassium TRESK channel. JCI Insight 2019; 4:130402. [PMID: 31484832 DOI: 10.1172/jci.insight.130402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022] Open
Abstract
Research shows that rats and humans on a high-fat diet (HFD) are less sensitive to satiety signals known to act via vagal afferent pathways. We hypothesize that HFD causes an upregulation of 2-pore domain potassium channels, resulting in hyperpolarization of nodose ganglia (NG) and decreased vagal response to satiety signals, which contribute to hyperphagia. We show that a 2-week HFD caused an upregulation of 2-pore domain TWIK-related spinal cord K+ (TRESK) and TWIK-related acid-sensitive K+ 1 (TASK1) channels by 330% ± 50% and 60% ± 20%, respectively, in NG. Patch-clamp studies of isolated NG neurons demonstrated a decrease in excitability. In vivo single-unit NG recordings showed that a 2-week HFD led to a 55% reduction in firing frequency in response to CCK-8 or leptin stimulation. NG electroporation with TRESK siRNA restored NG responsiveness to CCK-8 and leptin. Rats fed a 2-week HFD consumed ~40% more calories compared with controls. Silencing NG TRESK but not TASK1 channel expression in HFD-fed rats restored normal calorie consumption. In conclusion, HFD caused upregulation of TRESK channels, resulting in NG hyperpolarization and decreased vagal responsiveness to satiety signals. This finding provides a pharmacological target to prevent or treat HFD-induced hyperphagia.
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Peng M, Coutts D, Wang T, Cakmak YO. Systematic review of olfactory shifts related to obesity. Obes Rev 2019; 20:325-338. [PMID: 30450791 DOI: 10.1111/obr.12800] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 10/07/2018] [Indexed: 02/01/2023]
Abstract
OBJECTIVE The modern food environment is a key driver of rising levels of obesity. While olfaction is known to play a major role in food choice; however, its relationship to obesity is yet to be understood. This review assesses current knowledge of the interaction between obesity and olfaction. METHODS This review is based on observational studies comparing olfactory abilities across weight groups (N = 10) and clinical studies evaluating olfactory changes following bariatric surgery (N = 9). Meta-analyses were performed on data collected by a standard olfactory assessment tool (Sniffin΄ Sticks), to test whether olfaction has any association with body weight or bariatric surgery. RESULTS This review synthesizes findings derived from 38 datasets, with a total of 1432 individual olfactory assessments. The meta-analyses suggest that olfactory function is negatively correlated with body weight. In addition, Roux-en-Y gastric bypass patients frequently report olfactory changes, yet more pronounced and immediate shifts have been observed among sleeve gastrectomy recipients. CONCLUSIONS Our review finds strong evidence for the link between olfaction and obesity and indicates that bariatric surgery (particularly the sleeve gastrectomy) is effective in reversing olfactory decline associated with obesity. In conclusion, we present mechanistic models to underpin the observed relationship between olfaction and obesity.
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Affiliation(s)
- Mei Peng
- Sensory Neuroscience Laboratory, Department of Food Science, University of Otago, Dunedin, New Zealand
| | - Duncan Coutts
- Sensory Neuroscience Laboratory, Department of Food Science, University of Otago, Dunedin, New Zealand
| | - Ting Wang
- Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand
| | - Yusuf O Cakmak
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, Dunedin, New Zealand.,Medical Technologies Centre of Research Excellence, Auckland, New Zealand
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Wang L, Jacobs JP, Lagishetty V, Yuan PQ, Wu SV, Million M, Reeve JR, Pisegna JR, Taché Y. High-protein diet improves sensitivity to cholecystokinin and shifts the cecal microbiome without altering brain inflammation in diet-induced obesity in rats. Am J Physiol Regul Integr Comp Physiol 2017; 313:R473-R486. [PMID: 28724546 DOI: 10.1152/ajpregu.00105.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/14/2022]
Abstract
High-protein diet (HPD) curtails obesity and/or fat mass, but it is unknown whether it reverses neuroinflammation or alters glucose levels, CCK sensitivity, and gut microbiome in rats fed a Western diet (WD)-induced obesity (DIO). Male rats fed a WD (high fat and sugar) for 12 wk were switched to a HPD for 6 wk. Body composition, food intake, meal pattern, sensitivity to intraperitoneal CCK-8S, blood glucose, brain signaling, and cecal microbiota were assessed. When compared with a normal diet, WD increased body weight (9.3%) and fat mass (73.4%). CCK-8S (1.8 or 5.2 nmol/kg) did not alter food intake and meal pattern in DIO rats. Switching to a HPD for 6 wk reduced fat mass (15.7%) with a nonsignificantly reduced body weight gain, normalized blood glucose, and decreased feeding after CCK-8S. DIO rats on the WD or switched to a HPD showed comparable microbial diversity. However, in HPD versus WD rats, there was enrichment of 114 operational taxonomic units (OTUs) and depletion of 188 OTUs. Of those, Akkermansia muciniphila (enriched on a HPD), an unclassified Clostridiales, a member of the RF39 order, and a Phascolarctobacterium were significantly associated with fat mass. The WD increased cytokine expression in the hypothalamus and dorsal medulla that was unchanged by switching to HPD. These data indicate that HPD reduces body fat and restores glucose homeostasis and CCK sensitivity, while not modifying brain inflammation. In addition, expansion of cecal Akkermansia muciniphila correlated to fat mass loss may represent a potential peripheral mechanism of HPD beneficial effects.
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Affiliation(s)
- Lixin Wang
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Jonathan P Jacobs
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Venu Lagishetty
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Pu-Qing Yuan
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Shuping V Wu
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Mulugeta Million
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Joseph R Reeve
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
| | - Joseph R Pisegna
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and.,Division of Gastroenterology, Hepatology and Parenteral Nutrition, and Research and Development, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
| | - Yvette Taché
- CURE/Digestive Diseases Research Center and Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Digestive Diseases Division, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California; and
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Ndjim M, Poinsignon C, Parnet P, Le Dréan G. Loss of Vagal Sensitivity to Cholecystokinin in Rats Born with Intrauterine Growth Retardation and Consequence on Food Intake. Front Endocrinol (Lausanne) 2017; 8:65. [PMID: 28443064 PMCID: PMC5385335 DOI: 10.3389/fendo.2017.00065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/23/2017] [Indexed: 01/05/2023] Open
Abstract
Perinatal malnutrition is associated with low birth weight and an increased risk of developing metabolic syndrome in adulthood. Modification of food intake (FI) regulation was observed in adult rats born with intrauterine growth retardation induced by maternal dietary protein restriction during gestation and maintained restricted until weaning. Gastrointestinal peptides and particularly cholecystokinin (CCK) play a major role in short-term regulation of FI by relaying digestive signals to the hindbrain via the vagal afferent nerve (VAN). We hypothesized that vagal sensitivity to CCK could be affected in rats suffering from undernutrition [low protein (LP)] during fetal and postnatal life, leading to an altered gut-brain communication and impacting satiation. Our aim was to study short-term FI along with signals of appetite and satiation in adult LP rats compared to control rats. The dose-response to CCK injection was investigated on FI as well as the associated signaling pathways activated in nodose ganglia. We showed that LP rats have a reduced first-meal satiety ratio after a fasting period associated to a higher postprandial plasmatic CCK release, a reduced sensitivity to CCK when injected at low concentration and a reduced presence of CCK-1 receptor in nodose ganglia. Accordingly, the lower basal and CCK-induced phosphorylation of calcium/calmodulin-dependent protein kinase in nodose ganglia of LP rats could reflect an under-expressed vanilloid family of transient receptor potential cation channels on VAN. Altogether, the present data demonstrated a reduced vagal sensitivity to CCK in LP rats at adulthood, which could contribute to deregulation of FI reported in this model.
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Affiliation(s)
- Marième Ndjim
- UMR 1280 PHAN, INRA, Université de Nantes, Institut des Maladies de l’Appareil Digestif (IMAD), Centre de Recherche en Nutrition Humaine Ouest (CRNH Ouest), Nantes, France
| | - Camille Poinsignon
- UMR 1280 PHAN, INRA, Université de Nantes, Institut des Maladies de l’Appareil Digestif (IMAD), Centre de Recherche en Nutrition Humaine Ouest (CRNH Ouest), Nantes, France
| | - Patricia Parnet
- UMR 1280 PHAN, INRA, Université de Nantes, Institut des Maladies de l’Appareil Digestif (IMAD), Centre de Recherche en Nutrition Humaine Ouest (CRNH Ouest), Nantes, France
| | - Gwenola Le Dréan
- UMR 1280 PHAN, INRA, Université de Nantes, Institut des Maladies de l’Appareil Digestif (IMAD), Centre de Recherche en Nutrition Humaine Ouest (CRNH Ouest), Nantes, France
- *Correspondence: Gwenola Le Dréan,
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Ma WW, Ding BJ, Wang LJ, Shao Y, Xiao R. Involvement of Nuclear Related Factor 2 Signaling Pathway in the Brain of Obese Rats and Obesity-Resistant Rats Induced by High-Fat Diet. J Med Food 2016; 19:404-9. [DOI: 10.1089/jmf.2015.3500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Wei-Wei Ma
- Beijing Key Laboratory of Enviromental Toxicology, School of Public Health, Capital Medical University, Beijing, China
| | - Bing-Jie Ding
- Department of Clinical Nutrition, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Li-Jing Wang
- Beijing Key Laboratory of Enviromental Toxicology, School of Public Health, Capital Medical University, Beijing, China
| | - Yi Shao
- Beijing Key Laboratory of Enviromental Toxicology, School of Public Health, Capital Medical University, Beijing, China
| | - Rong Xiao
- Beijing Key Laboratory of Enviromental Toxicology, School of Public Health, Capital Medical University, Beijing, China
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Ma W, Yuan L, Yu H, Xi Y, Xiao R. Mitochondrial dysfunction and oxidative damage in the brain of diet-induced obese rats but not in diet-resistant rats. Life Sci 2014; 110:53-60. [PMID: 25058918 DOI: 10.1016/j.lfs.2014.07.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/19/2014] [Accepted: 07/12/2014] [Indexed: 12/11/2022]
Abstract
AIMS It has been suggested that obesity triggered by consuming a high-fat diet (HF) can account for oxidative damage and mitochondrial dysfunction. Thus, we aim to explore the oxidative stress and mitochondrial dysfunction detected in the brain of diet-induced obese (DIO) rats. MAIN METHODS Sprague-Dawley (SD) rats were fed either a HF diet or a normal-fat (NF) diet for 10weeks to obtain the control (CON), DIO and diet-resistant (DR) rats. d-Galactose was injected subcutaneously for 10weeks to establish oxidative stress model (MOD) rats. Then, the levels of total antioxidant capacity (T-AOC), lipid peroxidation (LPO), malondialdehyde (MDA), both in plasma and brain tissue, and catalase (CAT) in plasma were measured using enzymic assay kits and the levels of ghrelin, neuropeptide Y (NPY) and leptin in both plasma and brain tissue were measured by using enzyme-linked immunosorbent assay (ELISA) kits. Mitochondrial reactive oxygen species (ROS) formation in brain tissues was detected with 2, 7-dichlorofluorescein diacetate (DCFH2-DA) dyeing. The mitochondrial membrane potential (MMP) was measured with tetrachloro-tetraethyl benzimidazol carbocyanine iodide (JC-1) by a flow cytometer. KEY FINDINGS HF diet leads to an obese or DR state characterized by increased or decreased adiposity. The HF diet increased brain LPO, which was accompanied by lower ghrelin levels in DIO rats compared with DR rats. In addition, the increased mitochondrial ROS and lower MMP were detected in DIO rat comparing with DR rats. SIGNIFICANCE The current results demonstrated that mitochondrial dysfunction and oxidative damage in the brains of DIO rats, induced by HF diets, might be measurable.
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Affiliation(s)
- Weiwei Ma
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China
| | - Linhong Yuan
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China
| | - Huanling Yu
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China
| | - Yuandi Xi
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China
| | - Rong Xiao
- School of Public Health, Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China.
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11
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Duca FA, Sakar Y, Covasa M. The modulatory role of high fat feeding on gastrointestinal signals in obesity. J Nutr Biochem 2014; 24:1663-77. [PMID: 24041374 DOI: 10.1016/j.jnutbio.2013.05.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/13/2013] [Accepted: 05/28/2013] [Indexed: 01/03/2023]
Abstract
The gastrointestinal (GI) tract is a specialized sensory system that detects and responds to constant changes in nutrient- and bacterial-derived intestinal signals, thus contributing to controls of food intake. Chronic exposure to dietary fat causes morphological, physiological and metabolic changes leading to disruptions in the regulatory feeding pathways promoting more efficient fat absorption and utilization, blunted satiation signals and excess adiposity. Accumulating evidence demonstrates that impaired gastrointestinal signals following long-term high fat consumption are, at least partially, responsible for increased caloric intake. This review focuses on the role of dietary fat in modulating oral and post-oral chemosensory signaling elements responsible for lipid detection and responses, including changes in sensitivity to satiation signals, such as GLP-1, PYY and CCK and their impact on food intake and weight gain. Furthermore, the influence of the gut microbiota on mechanisms controlling energy regulation in the face of excessive fat exposure will be explored. The profound influence of dietary fats on altering complex regulatory feeding pathways can result in dysregulation of body weight and development of obesity, while restoration or manipulation of satiation signaling may prove an effective tool in prevention and treatment of obesity.
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Affiliation(s)
- Frank A Duca
- INRA, UMR 1319 Micalis, F-78352 Jouy-en-Josas, France; AgroParis Tech, UMR 1319, F-78352 Jouy-en-Josas, France; University Pierre and Marie Curie, 75006 Paris, France
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12
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Duca FA, Zhong L, Covasa M. Reduced CCK signaling in obese-prone rats fed a high fat diet. Horm Behav 2013; 64:812-7. [PMID: 24100196 DOI: 10.1016/j.yhbeh.2013.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/26/2013] [Accepted: 09/29/2013] [Indexed: 11/23/2022]
Abstract
Deficits in satiation signaling during obesogenic feeding have been proposed to play a role in hyperphagia and weight gain in animals prone to become obese. However, whether this impaired signaling is due to high fat (HF) feeding or to their obese phenotype is still unknown. Therefore, in the current study, we examined the effects of CCK-8 (0.5, 1.0, 2.0, and 4.0 μg/kg) on suppression of food intake of HF-fed obese prone (OP) and resistant (OR) rats. Additionally, we determined the role of endogenous CCK in lipid-induced satiation by measuring plasma CCK levels following a lipid gavage, and tested the effect of pretreatment with devazepide, a CCK-1R antagonist on intragastric lipid-induced satiation. Finally, we examined CCK-1R mRNA levels in the nodose ganglia. We show that OP rats have reduced feeding responses to the low doses of exogenous CCK-8 compared to OR rats. Furthermore, OP rats exhibit deficits in endogenous CCK signaling, as pretreatment with devazepide failed to abolish the reduction in food intake following lipid gavage. These effects were associated with reduced plasma CCK after intragastric lipid in OP but not OR rats. Furthermore, HF feeding resulted in downregulation of CCK-1Rs in the nodose ganglia of OP rats. Collectively, these results demonstrate that HF feeding leads to impairments in lipid-induced CCK satiation signaling in obese-prone rats, potentially contributing to hyperphagia and weight gain.
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Affiliation(s)
- Frank A Duca
- UMR1913-MICALIS, INRA, Domaine de Vilvert, Jouy-en-Josas 78352, France; UMR1913-MICALIS, AgroParisTech, Domaine de Vilvert, Jouy-en-Josas, 78352, France; Doctoral School of Physiology and Pathophysiology, University Pierre and Marie Currie, 15 rue de l'Ecole de Médecine, Paris 75006, France
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Cluny NL, Baraboi ED, Mackie K, Burdyga G, Richard D, Dockray GJ, Sharkey KA. High fat diet and body weight have different effects on cannabinoid CB(1) receptor expression in rat nodose ganglia. Auton Neurosci 2013; 179:122-30. [PMID: 24145047 DOI: 10.1016/j.autneu.2013.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/20/2013] [Accepted: 09/23/2013] [Indexed: 01/21/2023]
Abstract
Energy balance is regulated, in part, by the orexigenic signaling pathways of the vagus nerve. Fasting-induced modifications in the expression of orexigenic signaling systems have been observed in vagal afferents of lean animals. Altered basal cannabinoid (CB1) receptor expression in the nodose ganglia in obesity has been reported. Whether altered body weight or a high fat diet modifies independent or additive changes in CB1 expression is unknown. We investigated the expression of CB1 and orexin 1 receptor (OX-1R) in the nodose ganglia of rats fed ad libitum or food deprived (24h), maintained on low or high fat diets (HFD), with differing body weights. Male Wistar rats were fed chow or HFD (diet-induced obese: DIO or diet-resistant: DR) or were body weight matched to the DR group but fed chow (wmDR). CB1 and OX-1R immunoreactivity were investigated and CB1 mRNA density was determined using in situ hybridization. CB1 immunoreactivity was measured in fasted rats after sulfated cholecystokinin octapeptide (CCK8s) administration. In chow rats, fasting did not modify the level of CB1 mRNA. More CB1 immunoreactive cells were measured in fed DIO, DR and wmDR rats than chow rats; levels increased after fasting in chow and wmDR rats but not in DIO or DR rats. In HFD fasted rats CCK8s did not reduce CB1 immunoreactivity. OX-1R immunoreactivity was modified by fasting only in DR rats. These data suggest that body weight contributes to the proportion of neurons expressing CB1 immunoreactivity in the nodose ganglion, while HFD blunts fasting-induced increases, and CCK-induced suppression of, CB1-immunoreactivity.
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Affiliation(s)
- N L Cluny
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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Qinna NA, Akayleh FT, Al Remawi MM, Kamona BS, Taha H, Badwan AA. Evaluation of a functional food preparation based on chitosan as a meal replacement diet. J Funct Foods 2013. [DOI: 10.1016/j.jff.2013.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Lutz TA. Control of energy homeostasis by amylin. Cell Mol Life Sci 2012; 69:1947-65. [PMID: 22193913 PMCID: PMC11114503 DOI: 10.1007/s00018-011-0905-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/13/2011] [Accepted: 12/06/2011] [Indexed: 02/04/2023]
Abstract
Amylin is an important control of nutrient fluxes because it reduces energy intake, modulates nutrient utilization by inhibiting postprandial glucagon secretion, and increases energy disposal by preventing compensatory decreases of energy expenditure in weight-reduced individuals. The best investigated function of amylin which is cosecreted with insulin is to reduce eating by promoting meal-ending satiation. This effect is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites to mediate amylin action include the nucleus of the solitary tract and the lateral parabrachial nucleus, which convey the neural signal to the lateral hypothalamic area and other hypothalamic nuclei. Amylin may also signal adiposity because plasma levels of amylin are increased in adiposity and because higher amylin concentrations in the brain result in reduced body weight gain and adiposity, while amylin receptor antagonists increase body adiposity. The central mechanisms involved in amylin's effect on energy expenditure are much less known. A series of recent experiments in animals and humans indicate that amylin is a promising option for anti-obesity therapy especially in combination with other hormones. The most extensive dataset is available for the combination therapy of amylin and leptin. Ongoing research focuses on the mechanisms of these interactions.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland.
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Duca FA, Swartz TD, Sakar Y, Covasa M. Decreased intestinal nutrient response in diet-induced obese rats: role of gut peptides and nutrient receptors. Int J Obes (Lond) 2012; 37:375-81. [PMID: 22546775 DOI: 10.1038/ijo.2012.45] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIMS Diet-induced obesity (DIO) is an excellent model for examining human obesity comprising both genotypic and environmental (diet) factors. Decreased responsiveness to peripheral satiety signaling may be responsible for the hyperphagia in this model. In this study, we investigated responses to nutrient-induced satiation in outbred DIO and DIO-resistant (DR) rats fed a high-energy/high-fat (HE/HF) diet as well as intestinal satiety peptide content, intestinal nutrient-responsive receptor abundance and vagal anorectic receptor expression. METHODS Outbred DIO and DR rats fed a HE/HF diet were tested for short-term feeding responses following nutrient (glucose and intralipid (IL)) gastric loads. Gene and protein expressions of intestinal satiety peptides and fatty acid-responsive receptors were examined from isolated proximal intestinal epithelial cells and cholecystokinin-1 receptor (CCK-1R) and leptin receptor (LepR) mRNA from the nodose ganglia of DIO and DR animals. RESULTS DIO rats were less responsive to IL- (P<0.05) but not glucose-induced suppression of food intake compared with DR rats. DIO rats exhibited decreased CCK, peptide YY (PYY) and glucagon-like peptide-1 (GLP-1; P<0.05 for each) protein expression compared with DR rats. Also, DIO rats expressed more G-protein-coupled receptor 40 (GPR40; P<0.0001), GPR41 (P<0.001) and GPR120 (P<0.01) relative to DR rats. Finally, there were no differences in mRNA expression for CCK-1R and LepR in the nodose ganglia of DIO and DR rats. CONCLUSIONS Development of DIO may be partly due to decreased fat-induced satiation through low levels of endogenous satiety peptides, and changes in intestinal nutrient receptors.
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Affiliation(s)
- F A Duca
- INRA, Centre de Recherche de Jouy-en-Josas, UMR 1319, MICALIS, Neurobiology of Ingestive Behavior, Domaine de Vilvert, Jouy-en-Josas, France
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de Lartigue G, Barbier de la Serre C, Espero E, Lee J, Raybould HE. Leptin resistance in vagal afferent neurons inhibits cholecystokinin signaling and satiation in diet induced obese rats. PLoS One 2012; 7:e32967. [PMID: 22412960 PMCID: PMC3296757 DOI: 10.1371/journal.pone.0032967] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 02/06/2012] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND AIMS The gastrointestinal hormone cholecystokinin (CCK) plays an important role in regulating meal size and duration by activating CCK1 receptors on vagal afferent neurons (VAN). Leptin enhances CCK signaling in VAN via an early growth response 1 (EGR1) dependent pathway thereby increasing their sensitivity to CCK. In response to a chronic ingestion of a high fat diet, VAN develop leptin resistance and the satiating effects of CCK are reduced. We tested the hypothesis that leptin resistance in VAN is responsible for reducing CCK signaling and satiation. RESULTS Lean Zucker rats sensitive to leptin signaling, significantly reduced their food intake following administration of CCK8S (0.22 nmol/kg, i.p.), while obese Zucker rats, insensitive to leptin, did not. CCK signaling in VAN of obese Zucker rats was reduced, preventing CCK-induced up-regulation of Y2 receptor and down-regulation of melanin concentrating hormone 1 receptor (MCH1R) and cannabinoid receptor (CB1). In VAN from diet-induced obese (DIO) Sprague Dawley rats, previously shown to become leptin resistant, we demonstrated that the reduction in EGR1 expression resulted in decreased sensitivity of VAN to CCK and reduced CCK-induced inhibition of food intake. The lowered sensitivity of VAN to CCK in DIO rats resulted in a decrease in Y2 expression and increased CB1 and MCH1R expression. These effects coincided with the onset of hyperphagia in DIO rats. CONCLUSIONS Leptin signaling in VAN is required for appropriate CCK signaling and satiation. In response to high fat feeding, the onset of leptin resistance reduces the sensitivity of VAN to CCK thus reducing the satiating effects of CCK.
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Affiliation(s)
- Guillaume de Lartigue
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Claire Barbier de la Serre
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Elvis Espero
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Jennifer Lee
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Helen E. Raybould
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
- * E-mail:
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Physiological Low Doses of Leptin and Cholecystokinin Induces Body Weight-Loss in Juvenile and Lean, but not in Adult-Obese Rats. Int J Pept Res Ther 2011. [DOI: 10.1007/s10989-011-9281-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Maclean PS, Bergouignan A, Cornier MA, Jackman MR. Biology's response to dieting: the impetus for weight regain. Am J Physiol Regul Integr Comp Physiol 2011; 301:R581-600. [PMID: 21677272 PMCID: PMC3174765 DOI: 10.1152/ajpregu.00755.2010] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 06/08/2011] [Indexed: 01/02/2023]
Abstract
Dieting is the most common approach to losing weight for the majority of obese and overweight individuals. Restricting intake leads to weight loss in the short term, but, by itself, dieting has a relatively poor success rate for long-term weight reduction. Most obese people eventually regain the weight they have worked so hard to lose. Weight regain has emerged as one of the most significant obstacles for obesity therapeutics, undoubtedly perpetuating the epidemic of excess weight that now affects more than 60% of U.S. adults. In this review, we summarize the evidence of biology's role in the problem of weight regain. Biology's impact is first placed in context with other pressures known to affect body weight. Then, the biological adaptations to an energy-restricted, low-fat diet that are known to occur in the overweight and obese are reviewed, and an integrative picture of energy homeostasis after long-term weight reduction and during weight regain is presented. Finally, a novel model is proposed to explain the persistence of the "energy depletion" signal during the dynamic metabolic state of weight regain, when traditional adiposity signals no longer reflect stored energy in the periphery. The preponderance of evidence would suggest that the biological response to weight loss involves comprehensive, persistent, and redundant adaptations in energy homeostasis and that these adaptations underlie the high recidivism rate in obesity therapeutics. To be successful in the long term, our strategies for preventing weight regain may need to be just as comprehensive, persistent, and redundant, as the biological adaptations they are attempting to counter.
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Affiliation(s)
- Paul S Maclean
- University of Colorado Anschutz Medical Campus, Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, Center for Human Nutrition, Denver, Colorado, USA.
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Stewart JE, Feinle-Bisset C, Keast RSJ. Fatty acid detection during food consumption and digestion: Associations with ingestive behavior and obesity. Prog Lipid Res 2011; 50:225-33. [PMID: 21356242 DOI: 10.1016/j.plipres.2011.02.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 02/22/2011] [Indexed: 12/28/2022]
Abstract
The inability of humans to adequately regulate fat consumption is a salient contributor to the development of obesity. The macronutrients, fat, protein and carbohydrate, within foods are detected at various stages of consumption, during which their digestive products, fatty acids, amino acids and sugars, interact with chemosensory cells within the oral epithelium (taste receptor cells) and gastrointestinal (GI) tract (enteroendocrine cells). This chemoreception initiates functional responses, including taste perception, peptide secretion and alterations in GI motility, that play an important role in liking of food, appetite regulation and satiety. This review will summarize the available evidence relating to the oral and GI regulation of fat intake and how chemoreception at both locations is associated with digestive behavior, satiety and weight regulation.
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Affiliation(s)
- Jessica E Stewart
- Centre for Physical Activity and Nutrition Research, Sensory Science Group, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia
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Genetic polymorphisms in the hypothalamic pathway in relation to subsequent weight change--the DiOGenes study. PLoS One 2011; 6:e17436. [PMID: 21390334 PMCID: PMC3044761 DOI: 10.1371/journal.pone.0017436] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 02/03/2011] [Indexed: 01/12/2023] Open
Abstract
Background Single nucleotide polymorphisms (SNPs) in genes encoding the components involved in the hypothalamic pathway may influence weight gain and dietary factors may modify their effects. Aim We conducted a case-cohort study to investigate the associations of SNPs in candidate genes with weight change during an average of 6.8 years of follow-up and to examine the potential effect modification by glycemic index (GI) and protein intake. Methods and Findings Participants, aged 20–60 years at baseline, came from five European countries. Cases (‘weight gainers’) were selected from the total eligible cohort (n = 50,293) as those with the greatest unexplained annual weight gain (n = 5,584). A random subcohort (n = 6,566) was drawn with the intention to obtain an equal number of cases and noncases (n = 5,507). We genotyped 134 SNPs that captured all common genetic variation across the 15 candidate genes; 123 met the quality control criteria. Each SNP was tested for association with the risk of being a ‘weight gainer’ (logistic regression models) in the case-noncase data and with weight gain (linear regression models) in the random subcohort data. After accounting for multiple testing, none of the SNPs was significantly associated with weight change. Furthermore, we observed no significant effect modification by dietary factors, except for SNP rs7180849 in the neuromedin β gene (NMB). Carriers of the minor allele had a more pronounced weight gain at a higher GI (P = 2×10−7). Conclusions We found no evidence of association between SNPs in the studied hypothalamic genes with weight change. The interaction between GI and NMB SNP rs7180849 needs further confirmation.
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Borg J, Simrén M, Ohlsson B. Oxytocin reduces satiety scores without affecting the volume of nutrient intake or gastric emptying rate in healthy subjects. Neurogastroenterol Motil 2011; 23:56-61, e5. [PMID: 20868426 DOI: 10.1111/j.1365-2982.2010.01599.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Oxytocin is expressed throughout the gastrointestinal tract and is released in response to a fatty meal. Administration of an oxytocin receptor antagonist prolongs the gastric emptying rate. The aim of this study was to examine the effect of oxytocin on gastric accommodation, gastric emptying time, and satiety after food intake. METHODS Ten healthy subjects participated in a slow satiety drinking test with a liquid meal. Every 5 min the subjects scored their sensation of satiety using a visual analogue scale (VAS) until maximum satiety was reached and the amount of liquid intake was determined. Twelve subjects participated in a gastric emptying test. They were given a standardized meal containing 20 radio-opaque markers, after which fluoroscopy was performed and VAS was scored every hour. Both tests were performed four times during infusions of saline and three different oxytocin concentrations. Blood was collected for oxytocin concentration measurements. KEY RESULTS There were no differences in the volume of nutrient intake at maximum satiety between the three doses of oxytocin and saline. However, lower satiety scores at maximum satiety were seen after oxytocin infusion (P = 0.031), with 40 mU min(-1) being the most effective dosage (P = 0.013), and this was also true 30 min after finishing the meal (P = 0.032). There was no difference in gastric emptying time between saline and oxytocin. The oxytocin concentration in plasma was increased proportional to the oxytocin infusions. CONCLUSIONS & INFERENCES Infusion of oxytocin reduces satiety without affecting the volume of nutrient intake or gastric emptying in healthy subjects.
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Affiliation(s)
- J Borg
- Department of Clinical Sciences, Division of Gastroenterology and Hepatology, Skåne University Hospital, Malmö, Lund University, Lund, Sweden.
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Covasa M. Deficits in gastrointestinal responses controlling food intake and body weight. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1423-39. [PMID: 20861277 DOI: 10.1152/ajpregu.00126.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The gastrointestinal tract serves as a portal sensing incoming nutrients and relays mechanical and chemosensory signals of a meal to higher brain centers. Prolonged consumption of dietary fat causes adaptive changes within the alimentary, metabolic, and humoral systems that promote a more efficient process for energy metabolism from this rich source, leading to storage of energy in the form of adipose tissue. Furthermore, prolonged ingestion of dietary fats exerts profound effects on responses to signals involved in termination of a meal. This article reviews the effects of ingested fat on gastrointestinal motility, hormone release, and neuronal substrates. It focuses on changes in sensitivity to satiation signals resulting from chronic ingestion of high-fat diet, which may lead to disordered appetite and dysregulation of body weight.
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Affiliation(s)
- Mihai Covasa
- L'Institute National de la Recherche Agronomique, Centre de Recherche, Microbiologie de l'Alimentation au service de la Santé Humaine (MICALIS), Neurobiology of Ingestive Behavior, Jouy-en-Josas, France.
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