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Clarke GS, Li H, Ladyman SR, Young RL, Gatford KL, Page AJ. Effect of pregnancy on the expression of nutrient-sensors and satiety hormones in mice. Peptides 2024; 172:171114. [PMID: 37926186 DOI: 10.1016/j.peptides.2023.171114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/31/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
Small intestinal satiation pathways involve nutrient-induced stimulation of chemoreceptors leading to release of satiety hormones from intestinal enteroendocrine cells (ECCs). Whether adaptations in these pathways contribute to increased maternal food intake during pregnancy is unknown. To determine the expression of intestinal nutrient-sensors and satiety hormone transcripts and proteins across pregnancy in mice. Female C57BL/6J mice (10-12 weeks old) were randomized to mating and then tissue collection at early- (6.5 d), mid- (12.5 d) or late-pregnancy (17.5 d), or to an unmated age matched control group. Relative transcript expression of intestinal fatty acid, peptide and amino acid and carbohydrate chemoreceptors, as well as gut hormones was determined across pregnancy. The density of G-protein coupled receptor 93 (GPR93), free fatty acid receptor (FFAR) 4, cholecystokinin (CCK) and glucagon-like peptide1 (GLP-1) immunopositive cells was then compared between non-pregnant and late-pregnant mice. Duodenal GPR93 expression was lower in late pregnant than non-pregnant mice (P < 0.05). Ileal FFAR1 expression was higher at mid- than at early- or late-pregnancy. Ileal FFAR2 expression was higher at mid-pregnancy than in early pregnancy. Although FFAR4 expression was consistently lower in late-pregnant than non-pregnant mice (P < 0.001), the density of FFAR4 immunopositive cells was higher in the jejunum of late-pregnant than non-pregnant mice. A subset of protein and fatty acid chemoreceptor transcripts undergo region-specific change during murine pregnancy, which could augment hormone release and contribute to increased food intake. Further investigations are needed to determine the functional relevance of these changes.
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Affiliation(s)
- Georgia S Clarke
- School of Biomedicine, The University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, The 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
| | - Hui Li
- School of Biomedicine, The 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
| | - Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Richard L Young
- Adelaide Medical School, The 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
| | - Kathryn L Gatford
- School of Biomedicine, The University of Adelaide, Adelaide, SA 5005, Australia; Robinson Research Institute, The 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
- School of Biomedicine, The 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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Rose BD, Rimm EB, Zhang X, Sun Q, Huang T, Young RL, Ivey KL. You are What You Drink? How Associations Between Profiles of Beverage Consumption and Type 2 Diabetes Risk are Mediated by Biomarker Networks. Am J Clin Nutr 2023; 118:68-76. [PMID: 37061165 PMCID: PMC10447489 DOI: 10.1016/j.ajcnut.2023.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/02/2023] [Accepted: 04/12/2023] [Indexed: 04/17/2023] Open
Abstract
BACKGROUND Multiple studies have independently investigated the associations of the consumption of individual beverage types and specific plasma biomarkers with the risk of type 2 diabetes (T2D). However, as individuals do not consume single beverage types exclusively and plasma biomarkers do not act in isolation, it remains unclear how patterns of beverage consumption and plasma biomarker networks associate both with each other and T2D risk. OBJECTIVES We aimed to elucidate potential dietary determinants of T2D risk by defining a model that describes habitual beverage consumption profiles in relation to identified networks of circulating plasma biomarkers. METHODS This study included 1,461 case and 1,568 control participants from case-control studies of T2D nested within the Nurses' Health Study. Participants completed validated semiquantitative food frequency questionnaires that assessed habitual beverage consumption, and they provided blood samples from which 27 plasma biomarkers of cardiometabolic risk were identified. Common exploratory factor analysis (EFA) identified factors that separately described beverage consumption profiles and biomarker networks. Multivariable-adjusted regression elucidated the relationships between beverage and biomarker factors and T2D risk. RESULTS EFA revealed five factors describing unique beverage consumption profiles and seven factors describing biomarker networks. The factor describing alcoholic beverage consumption was associated with a reduced risk of T2D (odds ratio [OR]: 0.50 [0.40, 0.64], P<0.001) mediated, in part, by the factor describing increased concentrations of adiponectin biomarkers (19.9% [12.0, 31.1] P = 0.004). The factor describing low-calorie sweetened beverage (LCSBs) consumption was associated with an increased risk of T2D (OR: 1.33 [1.03, 1.72], P = 0.021), and the factor describing lower concentrations of insulin-like growth factor binding proteins 1 and 2, and soluble leptin receptor, and increased leptin concentrations (P = 0.005). CONCLUSIONS Moderate alcohol consumption was associated with reduced T2D risk, mediated in part by increased circulating adiponectin. LCSB consumption was associated with both increased T2D risk and perturbed insulin-like growth factor and leptin signaling.
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Affiliation(s)
- Braden D Rose
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia
| | - Eric B Rimm
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, United States
| | - Xuehong Zhang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States; Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, United States
| | - Qi Sun
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, United States
| | - Tianyi Huang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA, United States
| | - Richard L Young
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia
| | - Kerry L Ivey
- Division of Aging, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States.
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Overduin TS, Wardill HR, Young RL, Page AJ, Gatford KL. Active glucose transport varies by small intestinal region and oestrous cycle stage in mice. Exp Physiol 2023; 108:865-873. [PMID: 37022128 PMCID: PMC10988461 DOI: 10.1113/ep091040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/28/2023] [Indexed: 04/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? Body mass and food intake change during the female ovarian cycle: does glucose transport by the small intestine also vary? What is the main finding and its importance? We have optimised Ussing chamber methodology to measure region-specific active glucose transport in the small intestine of adult C57BL/6 mice. Our study provides the first evidence that jejunal active glucose transport changes during the oestrous cycle in mice, and is higher at pro-oestrus than oestrus. These results demonstrate adaptation in active glucose uptake, concurrent with previously reported changes in food intake. ABSTRACT Food intake changes across the ovarian cycle in rodents and humans, with a nadir during the pre-ovulatory phase and a peak during the luteal phase. However, it is unknown whether the rate of intestinal glucose absorption also changes. We therefore mounted small intestinal sections from C57BL/6 female mice (8-9 weeks old) in Ussing chambers and measured active ex vivo glucose transport via the change in short-circuit current (∆Isc ) induced by glucose. Tissue viability was confirmed by a positive ∆Isc response to 100 µM carbachol following each experiment. Active glucose transport, assessed after addition of 5, 10, 25 or 45 mM d-glucose to the mucosal chamber, was highest at 45 mM glucose in the distal jejunum compared to duodenum and ileum (P < 0.01). Incubation with the sodium-glucose cotransporter 1 (SGLT1) inhibitor phlorizin reduced active glucose transport in a dose-dependent manner in all regions (P < 0.01). Active glucose uptake induced by addition of 45 mM glucose to the mucosal chamber in the absence or presence of phlorizin was assessed in jejunum at each oestrous cycle stage (n = 9-10 mice per stage). Overall, active glucose uptake was lower at oestrus compared to pro-oestrus (P = 0.025). This study establishes an ex vivo method to measure region-specific glucose transport in the mouse small intestine. Our results provide the first direct evidence that SGLT1-mediated glucose transport in the jejunum changes across the ovarian cycle. The mechanisms underlying these adaptations in nutrient absorption remain to be elucidated.
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Affiliation(s)
- T. Sebastian Overduin
- School of BiomedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Lifelong Health ThemeSouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
| | - Hannah R. Wardill
- School of BiomedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Precision Medicine ThemeSouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
| | - Richard L. Young
- Lifelong Health ThemeSouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
- Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Amanda J. Page
- School of BiomedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Lifelong Health ThemeSouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
| | - Kathryn L. Gatford
- School of BiomedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Lifelong Health ThemeSouth Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
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Wang X, Chen C, Xie C, Huang W, Young RL, Jones KL, Horowitz M, Rayner CK, Sun Z, Wu T. Serum bile acid response to oral glucose is attenuated in patients with early type 2 diabetes and correlates with 2-hour plasma glucose in individuals without diabetes. Diabetes Obes Metab 2022; 24:1132-1142. [PMID: 35238131 PMCID: PMC9540586 DOI: 10.1111/dom.14683] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 12/13/2022]
Abstract
AIM To determine the serum bile acid (BA) response to 75-g oral glucose in individuals without diabetes, and whether this is attenuated in patients with 'early' type 2 diabetes (T2D) and related to the glycaemic response at 2 hours in either group. METHODS Forty newly diagnosed, treatment-naïve Han Chinese T2D subjects and 40 age-, gender-, and body mass index-matched controls without T2D ingested a 75-g glucose drink after an overnight fast. Plasma glucose and serum concentrations of total and individual BAs, fibroblast growth factor-19 (FGF-19), total glucagon-like peptide-1 (GLP-1), and insulin, were measured before and 2 hours after oral glucose. RESULTS Fasting total BA levels were higher in T2D than control subjects (P < .05). At 2 hours, the BA profile exhibited a shift from baseline in both groups, with increases in conjugated BAs and/or decreases in unconjugated BAs. There were increases in total BA and FGF-19 levels in control (both P < .05), but not T2D, subjects. Plasma glucose concentrations at 2 hours related inversely to serum total BA levels in control subjects (r = -0.42, P = .006). Total GLP-1 and the insulin/glucose ratio were increased at 2 hours in both groups, and the magnitude of the increase was greater in control subjects. CONCLUSIONS The serum BA response to a 75-g oral glucose load is attenuated in patients with 'early' T2D, as is the secretion of FGF-19 and GLP-1, while in individuals without T2D it correlates with 2-hour plasma glucose levels. These observations support a role for BAs in the regulation of postprandial glucose metabolism.
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Affiliation(s)
- Xuyi Wang
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Department of Clinical NutritionSoutheast UniversityNanjingChina
| | - Chang Chen
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Cong Xie
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
| | - Weikun Huang
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
| | - Richard L. Young
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Nutrition, Diabetes & Gut Health, Lifelong Health ThemeSouth Australian Health & Medical Research InstituteAdelaideAustralia
| | - Karen L. Jones
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Endocrine and Metabolic UnitRoyal Adelaide HospitalAdelaide
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Endocrine and Metabolic UnitRoyal Adelaide HospitalAdelaide
| | - Christopher K. Rayner
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Department of Gastroenterology and HepatologyRoyal Adelaide HospitalAdelaideAustralia
| | - Zilin Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of MedicineSoutheast UniversityNanjing
| | - Tongzhi Wu
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good HealthThe University of AdelaideAdelaide
- Endocrine and Metabolic UnitRoyal Adelaide HospitalAdelaide
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Xie C, Huang W, Watson LE, Soenen S, Young RL, Jones KL, Horowitz M, Rayner CK, Wu T. Plasma GLP-1 Response to Oral and Intraduodenal Nutrients in Health and Type 2 Diabetes-Impact on Gastric Emptying. J Clin Endocrinol Metab 2022; 107:e1643-e1652. [PMID: 34791325 DOI: 10.1210/clinem/dgab828] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Indexed: 02/07/2023]
Abstract
CONTEXT Both gastric emptying and the secretion of glucagon-like peptide-1 (GLP-1) are major determinants of postprandial glycemia in health and type 2 diabetes (T2D). GLP-1 secretion after a meal is dependent on the entry of nutrients into the small intestine, which, in turn, slows gastric emptying. OBJECTIVE To define the relationship between gastric emptying and the GLP-1 response to both oral and small intestinal nutrients in subjects with and without T2D. METHODS We evaluated: (i) the relationship between gastric emptying (breath test) and postprandial GLP-1 levels after a mashed potato meal in 73 individuals with T2D; (ii) inter-individual variations in GLP-1 response to (a) intraduodenal glucose (4 kcal/min) during euglycemia and hyperglycemia in 11 healthy and 12 T2D, subjects, (b) intraduodenal fat (2 kcal/min) in 15 T2D subjects, and (c) intraduodenal protein (3 kcal/min) in 10 healthy subjects; and (iii) the relationship between gastric emptying (breath test) of 75 g oral glucose and the GLP-1 response to intraduodenal glucose (4 kcal/min) in 21 subjects (9 healthy, 12 T2D). RESULTS The GLP-1 response to the mashed potato meal was unrelated to the gastric half-emptying time (T50). The GLP-1 responses to intraduodenal glucose, fat, and protein varied substantially between individuals, but intra-individual variation to glucose was modest. The T50 of oral glucose was related directly to the GLP-1 response to intraduodenal glucose (r = 0.65, P = 0.002). CONCLUSION In a given individual, gastric emptying is not a determinant of the postprandial GLP-1 response. However, the intrinsic gastric emptying rate is determined in part by the responsiveness of GLP-1 to intestinal nutrients.
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Affiliation(s)
- Cong Xie
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Weikun Huang
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Linda E Watson
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Stijn Soenen
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, QLD 4226, Australia
| | - Richard L Young
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute, Adelaide, SA 5000, Australia
| | - Karen L Jones
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - Christopher K Rayner
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - Tongzhi Wu
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA 5000, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
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Nunez-Salces M, Li H, Young RL, Page AJ. The secretion of total and acyl ghrelin from the mouse gastric mucosa: Role of nutrients and the lipid chemosensors FFAR4 and CD36. Peptides 2021; 146:170673. [PMID: 34627956 DOI: 10.1016/j.peptides.2021.170673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
AIMS This study investigated the nutrient-mediated modulation of total ghrelin (TG) and acyl ghrelin (AG) secretion from the mouse gastric mucosa, and the role of long-chain fatty acid chemosensors, FFAR4 and CD36, in lipid-mediated modulation of TG and AG release. METHODS Ex-vivo experiments were conducted using mouse gastric mucosa to examine the effects of nutrients (D-glucose, L-phenylalanine, peptone (mixture of oligopeptides & single amino acids), D-mannitol, α-linolenic acid and fat emulsion (intralipid)) on TG and AG secretion. Additionally, inhibition of FFAR4 and CD36 on α-linolenic acid and intralipid-mediated regulation of TG and AG secretion was assessed. RESULTS TG and AG secretion were unaffected by glucose and D-mannitol. Peptone stimulated the release of TG and AG. In contrast, L-phenylalanine reduced AG secretion only. Intralipid reduced TG secretion and stimulated AG secretion, and α-linolenic acid reduced AG release, without affecting TG mobilisation. Modulation of ghrelin secretion by lipids occurred in an FFAR4 and CD36-independent manner. CONCLUSION Ghrelin secretion is modulated in a nutrient-specific manner by proteins and lipids, with TG and AG displaying independent responses to the same stimuli. In addition, FFAR4 and CD36 do not participate in modulation of TG and AG secretion by α-linolenic acid and intralipid.
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Affiliation(s)
- Maria Nunez-Salces
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Hui Li
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Richard L Young
- Intestinal Nutrient Sensing Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia.
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Clarke GS, Gatford KL, Young RL, Grattan DR, Ladyman SR, Page AJ. Maternal adaptations to food intake across pregnancy: Central and peripheral mechanisms. Obesity (Silver Spring) 2021; 29:1813-1824. [PMID: 34623766 DOI: 10.1002/oby.23224] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/17/2021] [Accepted: 04/11/2021] [Indexed: 12/17/2022]
Abstract
A sufficient and balanced maternal diet is critical to meet the nutritional demands of the developing fetus and to facilitate deposition of fat reserves for lactation. Multiple adaptations occur to meet these energy requirements, including reductions in energy expenditure and increases in maternal food intake. The central nervous system plays a vital role in the regulation of food intake and energy homeostasis and responds to multiple metabolic and nutrient cues, including those arising from the gastrointestinal tract. This review describes the nutrient requirements of pregnancy and the impact of over- and undernutrition on the risk of pregnancy complications and adult disease in progeny. The central and peripheral regulation of food intake is then discussed, with particular emphasis on the adaptations that occur during pregnancy and the mechanisms that drive these changes, including the possible role of the pregnancy-associated hormones progesterone, estrogen, prolactin, and growth hormone. We identify the need for deeper mechanistic understanding of maternal adaptations, in particular, changes in gut-brain axis satiety signaling. Improved understanding of food intake regulation during pregnancy will provide a basis to inform strategies that prevent maternal under- or overnutrition, improve fetal health, and reduce the long-term health and economic burden for mothers and offspring.
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Affiliation(s)
- Georgia S Clarke
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Robinson Research Institute, Adelaide Medical School, The 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
| | - Kathryn L Gatford
- Robinson Research Institute, Adelaide Medical School, The 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
| | - Richard L Young
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia
- Intestinal Nutrient Sensing Group, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence: Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The 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
- Centre of Research Excellence: Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
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Sun EW, Iepsen EW, Pezos N, Lumsden AL, Martin AM, Schober G, Isaacs NJ, Rayner CK, Nguyen NQ, de Fontgalland D, Rabbitt P, Hollington P, Wattchow DA, Hansen T, Holm JC, Liou AP, Jackson VM, Torekov SS, Young RL, Keating DJ. A Gut-Intrinsic Melanocortin Signaling Complex Augments L-Cell Secretion in Humans. Gastroenterology 2021; 161:536-547.e2. [PMID: 33848536 DOI: 10.1053/j.gastro.2021.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/04/2021] [Accepted: 04/06/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Hypothalamic melanocortin 4 receptors (MC4R) are a key regulator of energy homeostasis. Brain-penetrant MC4R agonists have failed, as concentrations required to suppress food intake also increase blood pressure. However, peripherally located MC4R may also mediate metabolic benefits of MC4R activation. Mc4r transcript is enriched in mouse enteroendocrine L cells and peripheral administration of the endogenous MC4R agonist, α-melanocyte stimulating hormone (α-MSH), triggers the release of the anorectic hormones Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) in mice. This study aimed to determine whether pathways linking MC4R and L-cell secretion exist in humans. DESIGN GLP-1 and PYY levels were assessed in body mass index-matched individuals with or without loss-of-function MC4R mutations following an oral glucose tolerance test. Immunohistochemistry was performed on human intestinal sections to characterize the mucosal MC4R system. Static incubations with MC4R agonists were carried out on human intestinal epithelia, GLP-1 and PYY contents of secretion supernatants were assayed. RESULTS Fasting PYY levels and oral glucose-induced GLP-1 secretion were reduced in humans carrying a total loss-of-function MC4R mutation. MC4R was localized to L cells and regulates GLP-1 and PYY secretion from ex vivo human intestine. α-MSH immunoreactivity in the human intestinal epithelia was predominantly localized to L cells. Glucose-sensitive mucosal pro-opiomelanocortin cells provide a local source of α-MSH that is essential for glucose-induced GLP-1 secretion in small intestine. CONCLUSION Our findings describe a previously unidentified signaling nexus in the human gastrointestinal tract involving α-MSH release and MC4R activation on L cells in an autocrine and paracrine fashion. Outcomes from this study have direct implications for targeting mucosal MC4R to treat human metabolic disorders.
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Affiliation(s)
- Emily W Sun
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Eva W Iepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Nektaria Pezos
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Amanda L Lumsden
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Alyce M Martin
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Gudrun Schober
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Nichole J Isaacs
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Christopher K Rayner
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Nam Q Nguyen
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Torben Hansen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens-Christian Holm
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark; Department of Pediatrics, Holbæk University Hospital, Holbæk, Denmark
| | - Alice P Liou
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - V Margaret Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Richard L Young
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia.
| | - Damien J Keating
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia.
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9
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Overduin TS, Page AJ, Young RL, Gatford KL. Adaptations in gastrointestinal nutrient absorption and its determinants during pregnancy in monogastric mammals: a scoping review protocol. JBI Evid Synth 2021; 20:640-646. [PMID: 35165214 DOI: 10.11124/jbies-21-00025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The aim of this review is to characterize the current state of literature and knowledge regarding adaptations of gastrointestinal nutrient absorption, and the determinants of this absorption during pregnancy in monogastric mammals. INTRODUCTION Energy demands increase significantly during pregnancy due to the metabolic demands associated with placental and fetal growth, and the deposition of fat stores that support postnatal lactation. Previous studies have examined anatomical changes within the small intestine, but have focused on specific pregnancy stages or specific regions of the small intestine. Importantly, little is known about changes in nutrient absorption during pregnancy, and the underlying mechanisms that lead to these changes. An understanding of these adaptations will inform research to improve pregnancy outcomes for both mothers and newborns in the future. INCLUSION CRITERIA This review will include primary literature that describes gastrointestinal nutrient absorption and/or its determinants during pregnancy in monogastric mammals, including humans and rodents. Only data for normal pregnancies will be included, and models of pathology and illness will be excluded. Studies must include comparisons between pregnant animals at known stages of pregnancy, and non-pregnant controls, or compare animals at different stages of pregnancy. METHODS The following databases will be searched for literature on this topic: PubMed, Scopus, Web of Science, Embase, MEDLINE, and ProQuest Dissertations and Theses. Evidence screening and selection will be carried out independently by two reviewers, and conflicts will be resolved through discussion with additional members of the review team. Data will be extracted and presented in tables and/or figures, together with a narrative summary.
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Affiliation(s)
- Teunis Sebastian Overduin
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - Amanda J Page
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Richard L Young
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Kathryn L Gatford
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia.,Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
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10
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Sun EW, Martin AM, de Fontgalland D, Sposato L, Rabbitt P, Hollington P, Wattchow DA, Colella AD, Chataway T, Wewer Albrechtsen NJ, Spencer NJ, Young RL, Keating DJ. Evidence for Glucagon Secretion and Function Within the Human Gut. Endocrinology 2021; 162:6127286. [PMID: 33534908 DOI: 10.1210/endocr/bqab022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Indexed: 11/19/2022]
Abstract
Glucagon is secreted by pancreatic α cells in response to hypoglycemia and increases hepatic glucose output through hepatic glucagon receptors (GCGRs). There is evidence supporting the notion of extrapancreatic glucagon but its source and physiological functions remain elusive. Intestinal tissue samples were obtained from patients undergoing surgical resection of cancer. Mass spectrometry analysis was used to detect glucagon from mucosal lysate. Static incubations of mucosal tissue were performed to assess glucagon secretory response. Glucagon concentration was quantitated using a highly specific sandwich enzyme-linked immunosorbent assay. A cholesterol uptake assay and an isolated murine colonic motility assay were used to assess the physiological functions of intestinal GCGRs. Fully processed glucagon was detected by mass spectrometry in human intestinal mucosal lysate. High glucose evoked significant glucagon secretion from human ileal tissue independent of sodium glucose cotransporter and KATP channels, contrasting glucose-induced glucagon-like peptide 1 (GLP-1) secretion. The GLP-1 receptor agonist Exendin-4 attenuated glucose-induced glucagon secretion from the human ileum. GCGR blockade significantly increased cholesterol uptake in human ileal crypt culture and markedly slowed ex vivo colonic motility. Our findings describe the human gut as a potential source of extrapancreatic glucagon and demonstrate a novel enteric glucagon/GCGR circuit with important physiological functions beyond glycemic regulation.
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Affiliation(s)
- Emily W Sun
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Alyce M Martin
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | | | - Luigi Sposato
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Alexander D Colella
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Tim Chataway
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | | | - Nick J Spencer
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Richard L Young
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, SA, Australia
| | - Damien J Keating
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
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11
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Xie C, Huang W, Young RL, Jones KL, Horowitz M, Rayner CK, Wu T. Role of Bile Acids in the Regulation of Food Intake, and Their Dysregulation in Metabolic Disease. Nutrients 2021; 13:nu13041104. [PMID: 33800566 PMCID: PMC8066182 DOI: 10.3390/nu13041104] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Bile acids are cholesterol-derived metabolites with a well-established role in the digestion and absorption of dietary fat. More recently, the discovery of bile acids as natural ligands for the nuclear farnesoid X receptor (FXR) and membrane Takeda G-protein-coupled receptor 5 (TGR5), and the recognition of the effects of FXR and TGR5 signaling have led to a paradigm shift in knowledge regarding bile acid physiology and metabolic health. Bile acids are now recognized as signaling molecules that orchestrate blood glucose, lipid and energy metabolism. Changes in FXR and/or TGR5 signaling modulates the secretion of gastrointestinal hormones including glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), hepatic gluconeogenesis, glycogen synthesis, energy expenditure, and the composition of the gut microbiome. These effects may contribute to the metabolic benefits of bile acid sequestrants, metformin, and bariatric surgery. This review focuses on the role of bile acids in energy intake and body weight, particularly their effects on gastrointestinal hormone secretion, the changes in obesity and T2D, and their potential relevance to the management of metabolic disorders.
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Affiliation(s)
- Cong Xie
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
| | - Weikun Huang
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- The ARC Center of Excellence for Nanoscale BioPhotonics, Institute for Photonics and Advanced Sensing, School of Physical Sciences, The University of Adelaide, Adelaide 5005, Australia
| | - Richard L. Young
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute, Adelaide 5005, Australia
| | - Karen L. Jones
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide 5005, Australia
| | - Michael Horowitz
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide 5005, Australia
| | - Christopher K. Rayner
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide 5005, Australia
| | - Tongzhi Wu
- Adelaide Medical School, Center of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide 5005, Australia; (C.X.); (W.H.); (R.L.Y.); (K.L.J.); (M.H.); (C.K.R.)
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide 5005, Australia
- Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
- Correspondence:
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12
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Nunez‐Salces M, Li H, Feinle‐Bisset C, Young RL, Page AJ. The regulation of gastric ghrelin secretion. Acta Physiol (Oxf) 2021; 231:e13588. [PMID: 33249751 DOI: 10.1111/apha.13588] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022]
Abstract
Ghrelin is a gastric hormone with multiple physiological functions, including the stimulation of food intake and adiposity. It is well established that circulating ghrelin levels are closely associated with feeding patterns, rising strongly before a meal and lowering upon food intake. However, the mechanisms underlying the modulation of ghrelin secretion are not fully understood. The purpose of this review is to discuss current knowledge on the circadian oscillation of circulating ghrelin levels, the neural mechanisms stimulating fasting ghrelin levels and peripheral mechanisms modulating postprandial ghrelin levels. Furthermore, the therapeutic potential of targeting the ghrelin pathway is discussed in the context of the treatment of various metabolic disorders, including obesity, type 2 diabetes, diabetic gastroparesis and Prader-Willi syndrome. Moreover, eating disorders including anorexia nervosa, bulimia nervosa and binge-eating disorder are also discussed.
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Affiliation(s)
- Maria Nunez‐Salces
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
| | - Hui Li
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
| | - Christine Feinle‐Bisset
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
| | - Richard L. Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
- Intestinal Nutrient Sensing Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
| | - Amanda J. Page
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Xie C, Huang W, Wang X, Trahair LG, Pham HT, Marathe CS, Young RL, Jones KL, Horowitz M, Rayner CK, Wu T. Gastric emptying in health and type 2 diabetes: An evaluation using a 75 g oral glucose drink. Diabetes Res Clin Pract 2021; 171:108610. [PMID: 33301790 DOI: 10.1016/j.diabres.2020.108610] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/14/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
AIM Gastric emptying is a major determinant of the glycaemic response to carbohydrate and is frequently abnormal in type 2 diabetes (T2DM). There is little information about how chronic glycaemic control affects gastric emptying in T2DM. We evaluated gastric emptying of a 75 g glucose drink in community-based patients with T2DM of short duration with good or poor glycaemic control, and compared this to young and older controls. METHODS T2DM patients managed by diet and/or metformin, either well-controlled or poorly-controlled, together with young and age-matched older controls without diabetes, consumed a 75 g oral glucose drink containing 150 mg 13C-acetate for evaluation of gastric emptying (breath test) and blood glucose over 180 min. RESULTS The gastric half-emptying time (T50) was longer in the older than the young non-diabetic subjects (P = 0.041), but shorter in well-controlled T2DM patients than age-matched older controls (P = 0.043). The T50 in poorly-controlled T2DM patients was shorter than in older controls (P = 0.006), but similar to young non-diabetic subjects. CONCLUSIONS Gastric emptying of a glucose drink is delayed with ageing, but more rapid in patients with T2DM of relatively short duration, regardless of their glycaemic status. These observations support interventions that slow gastric emptying to improve postprandial glycaemia in these patients with T2DM.
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Affiliation(s)
- Cong Xie
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia
| | - Weikun Huang
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia
| | - Xuyi Wang
- Institute of Diabetes, School of Medicine, Southeast University, Nanjing, China
| | - Laurence G Trahair
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia
| | - Hung T Pham
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia
| | - Chinmay S Marathe
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute, Adelaide, Australia
| | - Richard L Young
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute, Adelaide, Australia
| | - Karen L Jones
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, Australia
| | - Christopher K Rayner
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Tongzhi Wu
- Adelaide Medical School and Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; Institute of Diabetes, School of Medicine, Southeast University, Nanjing, China; Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, Australia.
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15
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Nunez-Salces M, Li H, Feinle-Bisset C, Young RL, Page AJ. Nutrient-sensing components of the mouse stomach and the gastric ghrelin cell. Neurogastroenterol Motil 2020; 32:e13944. [PMID: 32666613 DOI: 10.1111/nmo.13944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/22/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The ability of the gut to detect nutrients is critical to the regulation of gut hormone secretion, food intake, and postprandial blood glucose control. Ingested nutrients are detected by specific gut chemosensors. However, knowledge of these chemosensors has primarily been derived from the intestine, while available information on gastric chemosensors is limited. This study aimed to investigate the nutrient-sensing repertoire of the mouse stomach with particular emphasis on ghrelin cells. METHODS Quantitative RT-PCR was used to determine mRNA levels of nutrient chemosensors (protein: G protein-coupled receptor 93 [GPR93], calcium-sensing receptor [CaSR], metabotropic glutamate receptor type 4 [mGluR4]; fatty acids: CD36, FFAR2&4; sweet/umami taste: T1R3), taste transduction components (TRPM5, GNAT2&3), and ghrelin and ghrelin-processing enzymes (PC1/3, ghrelin O-acyltransferase [GOAT]) in the gastric corpus and antrum of adult male C57BL/6 mice. Immunohistochemistry was performed to assess protein expression of chemosensors (GPR93, T1R3, CD36, and FFAR4) and their co-localization with ghrelin. KEY RESULTS Most nutrient chemosensors had higher mRNA levels in the antrum compared to the corpus, except for CD36, GNAT2, ghrelin, and GOAT. Similar regional distribution was observed at the protein level. At least 60% of ghrelin-positive cells expressed T1R3 and FFAR4, and over 80% expressed GPR93 and CD36. CONCLUSIONS AND INFERENCES The cellular mechanisms for the detection of nutrients are expressed in a region-specific manner in the mouse stomach and gastric ghrelin cells. These gastric nutrient chemosensors may play a role modulating gastrointestinal responses, such as the inhibition of ghrelin secretion following food intake.
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Affiliation(s)
- Maria Nunez-Salces
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Christine Feinle-Bisset
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Richard L Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia.,Intestinal Nutrient Sensing Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
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16
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Huang WK, Xie C, Young RL, Zhao JB, Ebendorff-Heidepriem H, Jones KL, Rayner CK, Wu TZ. Development of innovative tools for investigation of nutrient-gut interaction. World J Gastroenterol 2020; 26:3562-3576. [PMID: 32742126 PMCID: PMC7366065 DOI: 10.3748/wjg.v26.i25.3562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/29/2020] [Accepted: 06/17/2020] [Indexed: 02/06/2023] Open
Abstract
The gastrointestinal tract is the key interface between the ingesta and the human body. There is wide recognition that the gastrointestinal response to nutrients or bioactive compounds, particularly the secretion of numerous hormones, is critical to the regulation of appetite, body weight and blood glucose. This concept has led to an increasing focus on “gut-based” strategies for the management of metabolic disorders, including type 2 diabetes and obesity. Understanding the underlying mechanisms and downstream effects of nutrient-gut interactions is fundamental to effective translation of this knowledge to clinical practice. To this end, an array of research tools and platforms have been developed to better understand the mechanisms of gut hormone secretion from enteroendocrine cells. This review discusses the evolution of in vitro and in vivo models and the integration of innovative techniques that will ultimately enable the development of novel therapies for metabolic diseases.
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Affiliation(s)
- Wei-Kun Huang
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
- Institute for Photonics and Advanced Sensing, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- The ARC Centre of Excellence for Nanoscale BioPhotonics, Adelaide, SA 5005, Australia
| | - Cong Xie
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
| | - Richard L Young
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
- Diabetes, Nutrition and Gut Health, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, SA 5005, Australia
| | - Jiang-Bo Zhao
- Institute for Photonics and Advanced Sensing, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- The ARC Centre of Excellence for Nanoscale BioPhotonics, Adelaide, SA 5005, Australia
| | - Heike Ebendorff-Heidepriem
- Institute for Photonics and Advanced Sensing, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- The ARC Centre of Excellence for Nanoscale BioPhotonics, Adelaide, SA 5005, Australia
| | - Karen L Jones
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
| | - Christopher K Rayner
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - Tong-Zhi Wu
- Adelaide Medical School, Centre of Research Excellence in Translating Nutritional Science to Good Health, the University of Adelaide, Adelaide, SA 5005, Australia
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, Jiangsu Province, China
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17
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Malbert CH, Horowitz M, Young RL. Low-calorie sweeteners augment tissue-specific insulin sensitivity in a large animal model of obesity. Eur J Nucl Med Mol Imaging 2019; 46:2380-2391. [PMID: 31338548 DOI: 10.1007/s00259-019-04430-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 07/09/2019] [Indexed: 02/07/2023]
Abstract
PURPOSES Whether low-calorie sweeteners (LCS), such as sucralose and acesulfame K, can alter glucose metabolism is uncertain, particularly given the inconsistent observations relating to insulin resistance in recent human trials. We hypothesized that these discrepancies are accounted for by the surrogate tools used to evaluate insulin resistance and that PET 18FDG, given its capacity to quantify insulin sensitivity in individual organs, would be more sensitive in identifying changes in glucose metabolism. Accordingly, we performed a comprehensive evaluation of the effects of LCS on whole-body and organ-specific glucose uptake and insulin sensitivity in a large animal model of morbid obesity. METHODS Twenty mini-pigs with morbid obesity were fed an obesogenic diet enriched with LCS (sucralose 1 mg/kg/day and acesulfame K 0.5 mg/kg/day, LCS diet group), or without LCS (control group), for 3 months. Glucose uptake and insulin sensitivity were determined for the duodenum, liver, skeletal muscle, adipose tissue and brain using dynamic PET 18FDG scanning together with direct measurement of arterial input function. Body composition was also measured using CT imaging and energy metabolism quantified with indirect calorimetry. RESULTS The LCS diet increased subcutaneous abdominal fat by ≈ 20% without causing weight gain, and reduced insulin clearance by ≈ 40%, while whole-body glucose uptake and insulin sensitivity were unchanged. In contrast, glucose uptake in the duodenum, liver and brain increased by 57, 66 and 29% relative to the control diet group (P < 0.05 for all), while insulin sensitivity increased by 53, 55 and 28% (P < 0.05 for all), respectively. In the brain, glucose uptake increased significantly only in the frontal cortex, associated with improved metabolic connectivity towards the hippocampus and the amygdala. CONCLUSIONS In miniature pigs, the combination of sucralose and acesulfame K is biologically active. While not affecting whole-body insulin resistance, it increases insulin sensitivity and glucose uptake in specific tissues, mimicking the effects of obesity in the adipose tissue and in the brain.
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Affiliation(s)
- Charles-Henri Malbert
- Aniscan Unit, Department of Human Nutrition, INRA, 16, le clos, 35590, Saint-Gilles, France.
| | - Michael Horowitz
- Center of Research Excellence in Translating Nutrition to Good Health, The University of Adelaide, Adelaide, 5005, Australia
| | - Richard L Young
- Center of Research Excellence in Translating Nutrition to Good Health, The University of Adelaide, Adelaide, 5005, Australia
- Nutrition & Metabolism, South Australia Health & Medical Research Institute, Adelaide, 5000, Australia
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18
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Sun EW, Martin AM, Wattchow DA, de Fontgalland D, Rabbitt P, Hollington P, Young RL, Keating DJ. Metformin Triggers PYY Secretion in Human Gut Mucosa. J Clin Endocrinol Metab 2019; 104:2668-2674. [PMID: 30759215 DOI: 10.1210/jc.2018-02460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/07/2019] [Indexed: 01/13/2023]
Abstract
CONTEXT The antidiabetic drug metformin causes weight loss, but the underlying mechanisms are unclear. Recent clinical studies show that metformin increases plasma levels of the anorectic gut hormone, peptide YY (PYY), but whether this is through a direct effect on the gut is unknown. OBJECTIVE We hypothesized that exposure of human gut mucosal tissue to metformin would acutely trigger PYY secretion. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS Mucosal tissue was prepared from 46 human colonic and 9 ileal samples obtained after surgical resection and ex vivo secretion assays were performed. Tissue was exposed to metformin, as well as a series of other compounds as part of our mechanistic studies, in static incubations. Supernatant was sampled after 15 minutes. MAIN OUTCOME MEASURES PYY levels in supernatant, measured using ELISA. RESULTS Metformin increased PYY secretion from both ileal (P < 0.05) and colonic (P < 0.001) epithelia. Both basal and metformin-induced PYY secretion were unchanged across body mass index or in tissues obtained from individuals with type 2 diabetes. Metformin-dependent PYY secretion was blocked by inhibitors of the plasma membrane monoamine transporter (PMAT) and the serotonin reuptake transporter (SERT), as well as by an inhibitor of AMP kinase (AMPK). CONCLUSIONS This is a report of a direct action of metformin on the gut epithelium to trigger PYY secretion in humans, occurring via cell internalization through PMAT and SERT and intracellular activation of AMPK. Our results provide further support that the role of metformin in the treatment of metabolic syndrome has a gut-based component.
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Affiliation(s)
- Emily W Sun
- College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Alyce M Martin
- College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Dayan de Fontgalland
- Department of Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Damien J Keating
- College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
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19
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Zhang X, Young RL, Bound M, Hu S, Jones KL, Horowitz M, Rayner CK, Wu T. Comparative Effects of Proximal and Distal Small Intestinal Glucose Exposure on Glycemia, Incretin Hormone Secretion, and the Incretin Effect in Health and Type 2 Diabetes. Diabetes Care 2019; 42:520-528. [PMID: 30765429 DOI: 10.2337/dc18-2156] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/16/2019] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Cells releasing glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are distributed predominately in the proximal and distal gut, respectively. Hence, the region of gut exposed to nutrients may influence GIP and GLP-1 secretion and impact on the incretin effect and gastrointestinal-mediated glucose disposal (GIGD). We evaluated glycemic and incretin responses to glucose administered into the proximal or distal small intestine and quantified the corresponding incretin effect and GIGD in health and type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS Ten healthy subjects and 10 patients with T2DM were each studied on four occasions. On two days, a transnasal catheter was positioned with infusion ports opening 13 cm and 190 cm beyond the pylorus, and 30 g glucose with 3 g 3-O-methylglucose (a marker of glucose absorption) was infused into either site and 0.9% saline into the alternate site over 60 min. Matching intravenous isoglycemic clamp studies were performed on the other two days. Blood glucose, serum 3-O-methylglucose, and plasma hormones were evaluated over 180 min. RESULTS In both groups, blood glucose and serum 3-O-methylglucose concentrations were higher after proximal than distal glucose infusion (all P < 0.001). Plasma GLP-1 increased minimally after proximal, but substantially after distal, glucose infusion, whereas GIP increased promptly after both infusions, with concentrations initially greater, but less sustained, with proximal versus distal infusion (all P < 0.001). Both the incretin effect and GIGD were less with proximal than distal glucose infusion (both P ≤ 0.009). CONCLUSIONS The distal, as opposed to proximal, small intestine is superior in modulating postprandial glucose metabolism in both health and T2DM.
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Affiliation(s)
- Xiang Zhang
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Richard L Young
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Michelle Bound
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - Sanyuan Hu
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Karen L Jones
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - Tongzhi Wu
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Institute of Diabetes, School of Medicine, Southeast University, Nanjing, Jiangsu, China
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20
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Bahne E, Sun EWL, Young RL, Hansen M, Sonne DP, Hansen JS, Rohde U, Liou AP, Jackson ML, de Fontgalland D, Rabbitt P, Hollington P, Sposato L, Due S, Wattchow DA, Rehfeld JF, Holst JJ, Keating DJ, Vilsbøll T, Knop FK. Metformin-induced glucagon-like peptide-1 secretion contributes to the actions of metformin in type 2 diabetes. JCI Insight 2018; 3:93936. [PMID: 30518693 DOI: 10.1172/jci.insight.93936] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/24/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Metformin reduces plasma glucose and has been shown to increase glucagon-like peptide 1 (GLP-1) secretion. Whether this is a direct action of metformin on GLP-1 release, and whether some of the glucose-lowering effect of metformin occurs due to GLP-1 release, is unknown. The current study investigated metformin-induced GLP-1 secretion and its contribution to the overall glucose-lowering effect of metformin and underlying mechanisms in patients with type 2 diabetes. METHODS Twelve patients with type 2 diabetes were included in this placebo-controlled, double-blinded study. On 4 separate days, the patients received metformin (1,500 mg) or placebo suspended in a liquid meal, with subsequent i.v. infusion of the GLP-1 receptor antagonist exendin9-39 (Ex9-39) or saline. During 240 minutes, blood was sampled. The direct effect of metformin on GLP-1 secretion was tested ex vivo in human ileal and colonic tissue with and without dorsomorphin-induced inhibiting of the AMPK activity. RESULTS Metformin increased postprandial GLP-1 secretion compared with placebo (P = 0.014), and the postprandial glucose excursions were significantly smaller after metformin + saline compared with metformin + Ex9-39 (P = 0.004). Ex vivo metformin acutely increased GLP-1 secretion (colonic tissue, P < 0.01; ileal tissue, P < 0.05), but the effect was abolished by inhibition of AMPK activity. CONCLUSIONS Metformin has a direct and AMPK-dependent effect on GLP-1-secreting L cells and increases postprandial GLP-1 secretion, which seems to contribute to metformin's glucose-lowering effect and mode of action. TRIAL REGISTRATION NCT02050074 (https://clinicaltrials.gov/ct2/show/NCT02050074). FUNDING This study received grants from the A.P. Møller Foundation, the Novo Nordisk Foundation, the Danish Medical Association research grant, the Australian Research Council, the National Health and Medical Research Council, and Pfizer Inc.
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Affiliation(s)
- Emilie Bahne
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark
| | - Emily W L Sun
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Nutrition and Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Morten Hansen
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark
| | - David P Sonne
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Department of Clinical Pharmacology, Frederiksberg and Bispebjerg Hospital, University of Copenhagen, Denmark
| | - Jakob S Hansen
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark
| | - Ulrich Rohde
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark
| | - Alice P Liou
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, USA
| | - Margaret L Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, USA
| | - Dayan de Fontgalland
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Philippa Rabbitt
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Paul Hollington
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Luigi Sposato
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Steven Due
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - David A Wattchow
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia.,Nutrition and Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Tina Vilsbøll
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University Copenhagen, Copenhagen, Denmark
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21
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Little TJ, Cvijanovic N, DiPatrizio NV, Argueta DA, Rayner CK, Feinle-Bisset C, Young RL. Plasma endocannabinoid levels in lean, overweight, and obese humans: relationships to intestinal permeability markers, inflammation, and incretin secretion. Am J Physiol Endocrinol Metab 2018; 315:E489-E495. [PMID: 29438631 PMCID: PMC6230711 DOI: 10.1152/ajpendo.00355.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/05/2018] [Accepted: 02/06/2018] [Indexed: 12/12/2022]
Abstract
Intestinal production of endocannabinoid and oleoylethanolamide (OEA) is impaired in high-fat diet/obese rodents, leading to reduced satiety. Such diets also alter the intestinal microbiome in association with enhanced intestinal permeability and inflammation; however, little is known of these effects in humans. This study aimed to 1) evaluate effects of lipid on plasma anandamide (AEA), 2-arachidonyl- sn-glycerol (2-AG), and OEA in humans; and 2) examine relationships to intestinal permeability, inflammation markers, and incretin hormone secretion. Twenty lean, 18 overweight, and 19 obese participants underwent intraduodenal Intralipid infusion (2 kcal/min) with collection of endoscopic duodenal biopsies and blood. Plasma AEA, 2-AG, and OEA (HPLC/tandem mass spectrometry), tumor necrosis factor-α (TNFα), glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic peptide (GIP) (multiplex), and duodenal expression of occludin, zona-occludin-1 (ZO-1), intestinal-alkaline-phosphatase (IAP), and Toll-like receptor 4 (TLR4) (by RT-PCR) were assessed. Fasting plasma AEA was increased in obese compared with lean and overweight patients ( P < 0.05), with no effect of BMI group or ID lipid infusion on plasma 2-AG or OEA. Duodenal expression of IAP and ZO-1 was reduced in obese compared with lean ( P < 0.05), and these levels related negatively to plasma AEA ( P < 0.05). The iAUC for AEA was positively related to iAUC GIP ( r = 0.384, P = 0.005). Obese individuals have increased plasma AEA and decreased duodenal expression of ZO-1 and IAP compared with lean and overweight subjects. The relationships between plasma AEA with duodenal ZO-1, IAP, and GIP suggest that altered endocannabinoid signaling may contribute to changes in intestinal permeability, inflammation, and incretin release in human obesity.
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Affiliation(s)
- Tanya J Little
- University of Adelaide School of Medicine , Adelaide , Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide; Adelaide , Australia
| | - Nada Cvijanovic
- University of Adelaide School of Medicine , Adelaide , Australia
- South Australian Health and Medical Research Institute , Adelaide , Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide; Adelaide , Australia
| | - Nicholas V DiPatrizio
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Donovan A Argueta
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Christopher K Rayner
- University of Adelaide School of Medicine , Adelaide , Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide; Adelaide , Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital , Adelaide , Australia
| | - Christine Feinle-Bisset
- University of Adelaide School of Medicine , Adelaide , Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide; Adelaide , Australia
| | - Richard L Young
- University of Adelaide School of Medicine , Adelaide , Australia
- South Australian Health and Medical Research Institute , Adelaide , Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide; Adelaide , Australia
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22
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Xie C, Wang X, Young RL, Horowitz M, Rayner CK, Wu T. Role of Intestinal Bitter Sensing in Enteroendocrine Hormone Secretion and Metabolic Control. Front Endocrinol (Lausanne) 2018; 9:576. [PMID: 30319553 PMCID: PMC6171477 DOI: 10.3389/fendo.2018.00576] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/10/2018] [Indexed: 02/05/2023] Open
Abstract
The gastrointestinal tract stores ingested nutrients in the stomach which are then delivered to the small intestine at a controlled rate to optimize their digestion and absorption. The interaction of nutrients with the small and large intestine generates feedback that slows gastric emptying, induces satiation, and reduces postprandial glycemic excursions. The mechanisms underlying these nutrient-gut interactions are complex; it has only recently been appreciated that the gut has the capacity to detect intraluminal contents in much the same way as the tongue, via activation of specific G-protein-coupled receptors, and that ensuing signaling mechanisms modulate the release of an array of gut hormones that influence gastrointestinal motility, appetite and glycemia. Interestingly, evidence from preclinical models supports a functional link between intestinal bitter taste receptor (BTRs) and gastrointestinal hormone secretion, and the outcomes of recent studies indicate that stimulation of intestinal BTRs may be used to modulate gastrointestinal function, to diminish energy intake and limit postprandial blood glucose excursions in humans. This review summarizes current evidence about the expression and function of intestinal BTRs in relation to enteroendocrine hormone release and discusses the clinical implications of this pathway for the management of obesity and type 2 diabetes.
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Affiliation(s)
- Cong Xie
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
| | - Xuyi Wang
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
- Institute of Diabetes, School of Medicine, Southeast University, Nanjing, China
| | - Richard L. Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Michael Horowitz
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
| | - Christopher K. Rayner
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
| | - Tongzhi Wu
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, Australia
- Institute of Diabetes, School of Medicine, Southeast University, Nanjing, China
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23
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Young RL, Lumsden AL, Martin AM, Schober G, Pezos N, Thazhath SS, Isaacs NJ, Cvijanovic N, Sun EWL, Wu T, Rayner CK, Nguyen NQ, Fontgalland DD, Rabbitt P, Hollington P, Sposato L, Due SL, Wattchow DA, Liou AP, Jackson VM, Keating DJ. Augmented capacity for peripheral serotonin release in human obesity. Int J Obes (Lond) 2018; 42:1880-1889. [PMID: 29568107 DOI: 10.1038/s41366-018-0047-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 01/08/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND/OBJECTIVES Evidence from animal studies highlights an important role for serotonin (5-HT), derived from gut enterochromaffin (EC) cells, in regulating hepatic glucose production, lipolysis and thermogenesis, and promoting obesity and dysglycemia. Evidence in humans is limited, although elevated plasma 5-HT concentrations are linked to obesity. SUBJECTS/METHODS We assessed (i) plasma 5-HT concentrations before and during intraduodenal glucose infusion (4 kcal/min for 30 min) in non-diabetic obese (BMI 44 ± 4 kg/m2, N = 14) and control (BMI 24 ± 1 kg/m2, N = 10) subjects, (ii) functional activation of duodenal EC cells (immunodetection of phospho-extracellular related-kinase, pERK) in response to glucose, and in separate subjects, (iii) expression of tryptophan hydroxylase-1 (TPH1) in duodenum and colon (N = 39), and (iv) 5-HT content in primary EC cells from these regions (N = 85). RESULTS Plasma 5-HT was twofold higher in obese than control responders prior to (P = 0.025), and during (iAUC, P = 0.009), intraduodenal glucose infusion, and related positively to BMI (R2 = 0.334, P = 0.003) and HbA1c (R2 = 0.508, P = 0.009). The density of EC cells in the duodenum was twofold higher at baseline in obese subjects than controls (P = 0.023), with twofold more EC cells activated by glucose infusion in the obese (EC cells co-expressing 5-HT and pERK, P = 0.001), while the 5-HT content of EC cells in duodenum and colon was similar; TPH1 expression was 1.4-fold higher in the duodenum of obese subjects (P = 0.044), and related positively to BMI (R2 = 0.310, P = 0.031). CONCLUSIONS Human obesity is characterized by an increased capacity to produce and release 5-HT from the proximal small intestine, which is strongly linked to higher body mass, and glycemic control. Gut-derived 5-HT is likely to be an important driver of pathogenesis in human obesity and dysglycemia.
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Affiliation(s)
- Richard L Young
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda L Lumsden
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Alyce M Martin
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Gudrun Schober
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Nektaria Pezos
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Sony S Thazhath
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nicole J Isaacs
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Nada Cvijanovic
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Emily W L Sun
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Tongzhi Wu
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Christopher K Rayner
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nam Q Nguyen
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Dayan de Fontgalland
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Luigi Sposato
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Steven L Due
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Alice P Liou
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 02139, USA
| | - V Margaret Jackson
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 02139, USA
| | - Damien J Keating
- Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia. .,Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia.
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Kreuch D, Keating DJ, Wu T, Horowitz M, Rayner CK, Young RL. Gut Mechanisms Linking Intestinal Sweet Sensing to Glycemic Control. Front Endocrinol (Lausanne) 2018; 9:741. [PMID: 30564198 PMCID: PMC6288399 DOI: 10.3389/fendo.2018.00741] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 11/22/2018] [Indexed: 12/25/2022] Open
Abstract
Sensing nutrients within the gastrointestinal tract engages the enteroendocrine cell system to signal within the mucosa, to intrinsic and extrinsic nerve pathways, and the circulation. This signaling provides powerful feedback from the intestine to slow the rate of gastric emptying, limit postprandial glycemic excursions, and induce satiation. This review focuses on the intestinal sensing of sweet stimuli (including low-calorie sweeteners), which engage similar G-protein-coupled receptors (GPCRs) to the sweet taste receptors (STRs) of the tongue. It explores the enteroendocrine cell signals deployed upon STR activation that act within and outside the gastrointestinal tract, with a focus on the role of this distinctive pathway in regulating glucose transport function via absorptive enterocytes, and the associated impact on postprandial glycemic responses in animals and humans. The emerging role of diet, including low-calorie sweeteners, in modulating the composition of the gut microbiome and how this may impact glycemic responses of the host, is also discussed, as is recent evidence of a causal role of diet-induced dysbiosis in influencing the gut-brain axis to alter gastric emptying and insulin release. Full knowledge of intestinal STR signaling in humans, and its capacity to engage host and/or microbiome mechanisms that modify glycemic control, holds the potential for improved prevention and management of type 2 diabetes.
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Affiliation(s)
- Denise Kreuch
- Faculty of Health and Medical Sciences & Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Damien J. Keating
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Tongzhi Wu
- Faculty of Health and Medical Sciences & Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Michael Horowitz
- Faculty of Health and Medical Sciences & Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Christopher K. Rayner
- Faculty of Health and Medical Sciences & Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Richard L. Young
- Faculty of Health and Medical Sciences & Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- *Correspondence: Richard L. Young
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25
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Abstract
Enteroendocrine cells lining the gut epithelium constitute the largest endocrine organ in the body and secrete over 20 different hormones in response to cues from ingested foods and changes in nutritional status. Not only do these hormones convey signals from the gut to the brain via the gut-brain axis, they also act directly on metabolically important peripheral targets in a highly concerted fashion to maintain energy balance and glucose homeostasis. Gut-derived hormones released during fasting tend to be orexigenic and have hyperglycaemic potential. Conversely, gut hormones secreted postprandially generally promote satiety and facilitate glucose clearance. Although some of the metabolic benefits conferred by bariatric surgeries have been ascribed to changes in the secretory profiles of various gut hormones, the therapeutic potential of the enteroendocrine system as a viable target against metabolic diseases remain largely underexploited, except for incretin-mimetics. This review provides a brief overview of the physiological importance and highlights the therapeutic potential of the following gut hormones: serotonin, glucose-dependent insulinotropic peptide, glucagon-like peptide 1, oxyntomodulin, peptide YY, insulin-like peptide 5, and ghrelin.
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Affiliation(s)
- Emily W. L. Sun
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Alyce M. Martin
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Richard L. Young
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Damien J. Keating
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- *Correspondence: Damien J. Keating
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26
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Martin AM, Lumsden AL, Young RL, Jessup CF, Spencer NJ, Keating DJ. Regional differences in nutrient-induced secretion of gut serotonin. Physiol Rep 2017; 5:5/6/e13199. [PMID: 28320893 PMCID: PMC5371566 DOI: 10.14814/phy2.13199] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 12/17/2022] Open
Abstract
Enterochromaffin (EC) cells located in the gastrointestinal (GI) tract provide the vast majority of serotonin (5-HT) in the body and constitute half of all enteroendocrine cells. EC cells respond to an array of stimuli, including various ingested nutrients. Ensuing 5-HT release from these cells plays a diverse role in regulating gut motility as well as other important responses to nutrient ingestion such as glucose absorption and fluid balance. Recent data also highlight the role of peripheral 5-HT in various pathways related to metabolic control. Details related to the manner by which EC cells respond to ingested nutrients are scarce and as that the nutrient environment changes along the length of the gut, it is unknown whether the response of EC cells to nutrients is dependent on their GI location. The aim of the present study was to identify whether regional differences in nutrient sensing capability exist in mouse EC cells. We isolated mouse EC cells from duodenum and colon to demonstrate differential responses to sugars depending on location. Measurements of intracellular calcium concentration and 5-HT secretion demonstrated that colonic EC cells are more sensitive to glucose, while duodenal EC cells are more sensitive to fructose and sucrose. Short-chain fatty acids (SCFAs), which are predominantly synthesized by intestinal bacteria, have been previously associated with an increase in circulating 5-HT; however, we find that SCFAs do not acutely stimulate EC cell 5-HT release. Thus, we highlight that EC cell physiology is dictated by regional location within the GI tract, and identify differences in the regional responsiveness of EC cells to dietary sugars.
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Affiliation(s)
- Alyce M Martin
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia
| | - Amanda L Lumsden
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia
| | - Richard L Young
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Claire F Jessup
- Department of Anatomy and Histology and Centre for Neuroscience, Flinders University, Adelaide, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Nick J Spencer
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia .,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
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27
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Sun EW, de Fontgalland D, Rabbitt P, Hollington P, Sposato L, Due SL, Wattchow DA, Rayner CK, Deane AM, Young RL, Keating DJ. Mechanisms Controlling Glucose-Induced GLP-1 Secretion in Human Small Intestine. Diabetes 2017; 66:2144-2149. [PMID: 28385801 PMCID: PMC5860185 DOI: 10.2337/db17-0058] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/12/2017] [Indexed: 12/25/2022]
Abstract
Intestinal glucose stimulates secretion of the incretin hormone glucagon-like peptide 1 (GLP-1). The mechanisms underlying this pathway have not been fully investigated in humans. In this study, we showed that a 30-min intraduodenal glucose infusion activated half of all duodenal L cells in humans. This infusion was sufficient to increase plasma GLP-1 levels. With an ex vivo model using human gut tissue specimens, we showed a dose-responsive GLP-1 secretion in the ileum at ≥200 mmol/L glucose. In ex vivo tissue from the duodenum and ileum, but not the colon, 300 mmol/L glucose potently stimulated GLP-1 release. In the ileum, this response was independent of osmotic influences and required delivery of glucose via GLUT2 and mitochondrial metabolism. The requirement of voltage-gated Na+ and Ca2+ channel activation indicates that membrane depolarization occurs. KATP channels do not drive this, as tolbutamide did not trigger release. The sodium-glucose cotransporter 1 (SGLT1) substrate α-MG induced secretion, and the response was blocked by the SGLT1 inhibitor phlorizin or by replacement of extracellular Na+ with N-methyl-d-glucamine. This is the first report of the mechanisms underlying glucose-induced GLP-1 secretion from human small intestine. Our findings demonstrate a dominant role of SGLT1 in controlling glucose-stimulated GLP-1 release in human ileal L cells.
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Affiliation(s)
- Emily W Sun
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Philippa Rabbitt
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Paul Hollington
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Luigi Sposato
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Steven L Due
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - David A Wattchow
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Adam M Deane
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Intensive Care Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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Martin AM, Lumsden AL, Young RL, Jessup CF, Spencer NJ, Keating DJ. The nutrient-sensing repertoires of mouse enterochromaffin cells differ between duodenum and colon. Neurogastroenterol Motil 2017; 29. [PMID: 28251760 DOI: 10.1111/nmo.13046] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 01/30/2023]
Abstract
BACKGROUND Enterochromaffin (EC) cells within the gastrointestinal (GI) tract provide almost all body serotonin (5-hydroxytryptamine [5-HT]). Peripheral 5-HT, released from EC cells lining the gut wall, serves diverse physiological roles. These include modulating GI motility, bone formation, hepatic gluconeogenesis, thermogenesis, insulin resistance, and regulation of fat mass. Enterochromaffin cells are nutrient sensors, but which nutrients they are responsive to and how this changes in different parts of the GI tract are poorly understood. METHODS To accurately undertake such an examination, we undertook the first isolation and purification of primary mouse EC cells from both the duodenum and colon in the same animal. This allowed us to compare, in an internally controlled manner, regional differences in the expression of nutrient sensors in EC cells using real-time PCR. KEY RESULTS Both colonic and duodenal EC cells expressed G protein-coupled receptors and facilitative transporters for sugars, free fatty acids, amino acids, and lipid amides. We find differential expression of nutrient receptor and transporters in EC cells obtained from duodenal and colonic EC cells. Duodenal EC cells have higher expression of tryptophan hydroxylase-1, sugar transporters GLUT2, GLUT5, and free fatty acid receptors 1 and 3 (FFAR1 and FFAR3). Colonic EC cells express higher levels of GLUT1, FFAR2, and FFAR4. CONCLUSIONS & INFERENCES We highlight the diversity of EC cell physiology and identify differences in the regional sensing repertoire of EC cells to an assortment of nutrients. These data indicate that not all EC cells are similar and that differences in their physiological responses are likely dependent on their location within the GI tract.
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Affiliation(s)
- A M Martin
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
| | - A L Lumsden
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
| | - R L Young
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - C F Jessup
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,Department of Anatomy and Histology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
| | - N J Spencer
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
| | - D J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
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29
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Martin AM, Young RL, Leong L, Rogers GB, Spencer NJ, Jessup CF, Keating DJ. The Diverse Metabolic Roles of Peripheral Serotonin. Endocrinology 2017; 158:1049-1063. [PMID: 28323941 DOI: 10.1210/en.2016-1839] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 02/23/2017] [Indexed: 02/07/2023]
Abstract
Serotonin (5-hydroxytryptamine or 5-HT) is a multifunctional bioamine with important signaling roles in a range of physiological pathways. Almost all of the 5-HT in our bodies is synthesized in specialized enteroendocrine cells within the gastrointestinal (GI) mucosa called enterochromaffin (EC) cells. These cells provide all of our circulating 5-HT. We have long appreciated the important contributions of 5-HT within the gut, including its role in modulating GI motility. However, evidence of the physiological and clinical significance of gut-derived 5-HT outside of the gut has recently emerged, implicating 5-HT in regulation of glucose homeostasis, lipid metabolism, bone density, and diseases associated with metabolic syndrome, such as obesity and type 2 diabetes. Although a new picture has developed in the last decade regarding the various metabolic roles of peripheral serotonin, so too has our understanding of the physiology of EC cells. Given that they are scattered throughout the lining of the GI tract within the epithelial cell layer, these cells are typically difficult to study. Advances in isolation procedures now allow the study of pure EC-cell cultures and single cells, enabling studies of EC-cell physiology to occur. EC cells are sensory cells that are capable of integrating cues from ingested nutrients, the enteric nervous system, and the gut microbiome. Thus, levels of peripheral 5-HT can be modulated by a multitude of factors, resulting in both local and systemic effects for the regulation of a raft of physiological pathways related to metabolism and obesity.
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Affiliation(s)
- Alyce M Martin
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide 5042, Australia
| | - Richard L Young
- Nutrition and Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide 5001, Australia
- Adelaide Medical School, University of Adelaide, Adelaide 5005, Australia
| | - Lex Leong
- Infection and Immunity, SAHMRI, Adelaide 5001, Australia
- SAHMRI Microbiome Research Laboratory, School of Medicine, Flinders University of South Australia, Adelaide 5042, Australia
| | - Geraint B Rogers
- Infection and Immunity, SAHMRI, Adelaide 5001, Australia
- SAHMRI Microbiome Research Laboratory, School of Medicine, Flinders University of South Australia, Adelaide 5042, Australia
| | - Nick J Spencer
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide 5042, Australia
| | - Claire F Jessup
- Adelaide Medical School, University of Adelaide, Adelaide 5005, Australia
- Discipline of Anatomy and Histology, Flinders University of South Australia, Adelaide 5042, Australia
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide 5042, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide 5001, Australia
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Lumsden AL, Young RL, Pezos N, Keating DJ. Huntingtin-associated protein 1: Eutherian adaptation from a TRAK-like protein, conserved gene promoter elements, and localization in the human intestine. BMC Evol Biol 2016; 16:214. [PMID: 27737633 PMCID: PMC5064798 DOI: 10.1186/s12862-016-0780-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/29/2016] [Indexed: 11/28/2022] Open
Abstract
Background Huntingtin-associated Protein 1 (HAP1) is expressed in neurons and endocrine cells, and is critical for postnatal survival in mice. HAP1 shares a conserved “HAP1_N” domain with TRAfficking Kinesin proteins TRAK1 and TRAK2 (vertebrate), Milton (Drosophila) and T27A3.1 (C. elegans). HAP1, TRAK1 and TRAK2 have a degree of common function, particularly regarding intracellular receptor trafficking. However, TRAK1, TRAK2 and Milton (which have a “Milt/TRAK” domain that is absent in human and rodent HAP1) differ in function to HAP1 in that they are mitochondrial transport proteins, while HAP1 has emerging roles in starvation response. We have investigated HAP1 function by examining its evolution, and upstream gene promoter sequences. We performed phylogenetic analyses of the HAP1_N domain family of proteins, incorporating HAP1 orthologues (identified by genomic synteny) from 5 vertebrate classes, and also searched the Dictyostelium proteome for a common ancestor. Computational analyses of mammalian HAP1 gene promoters were performed to identify phylogenetically conserved regulatory motifs. Results We found that as recently as marsupials, HAP1 contained a Milt/TRAK domain and was more similar to TRAK1 and TRAK2 than to eutherian HAP1. The Milt/TRAK domain likely arose post multicellularity, as it was absent in the Dictyostelium proteome. It was lost from HAP1 in the eutherian lineage, and also from T27A3.1 in C. elegans. The HAP1 promoter from human, mouse, rat, rabbit, horse, dog, Tasmanian devil and opossum contained common sites for transcription factors involved in cell cycle, growth, differentiation, and stress response. A conserved arrangement of regulatory elements was identified, including sites for caudal-related homeobox transcription factors (CDX1 and CDX2), and myc-associated factor X (MAX) in the region of the TATA box. CDX1 and CDX2 are intestine-enriched factors, prompting investigation of HAP1 protein expression in the human duodenum. HAP1 was localized to singly dispersed mucosal cells, including a subset of serotonin-positive enterochromaffin cells. Conclusion We have identified eutherian HAP1 as an evolutionarily recent adaptation of a vertebrate TRAK protein-like ancestor, and found conserved CDX1/CDX2 and MAX transcription factor binding sites near the TATA box in mammalian HAP1 gene promoters. We also demonstrated that HAP1 is expressed in endocrine cells of the human gut. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0780-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amanda L Lumsden
- Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia.
| | - Richard L Young
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Nektaria Pezos
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Damien J Keating
- Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia. .,South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.
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31
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Rogers GB, Keating DJ, Young RL, Wong ML, Licinio J, Wesselingh S. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Mol Psychiatry 2016; 21:738-48. [PMID: 27090305 PMCID: PMC4879184 DOI: 10.1038/mp.2016.50] [Citation(s) in RCA: 560] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 02/22/2016] [Accepted: 02/25/2016] [Indexed: 02/06/2023]
Abstract
The human body hosts an enormous abundance and diversity of microbes, which perform a range of essential and beneficial functions. Our appreciation of the importance of these microbial communities to many aspects of human physiology has grown dramatically in recent years. We know, for example, that animals raised in a germ-free environment exhibit substantially altered immune and metabolic function, while the disruption of commensal microbiota in humans is associated with the development of a growing number of diseases. Evidence is now emerging that, through interactions with the gut-brain axis, the bidirectional communication system between the central nervous system and the gastrointestinal tract, the gut microbiome can also influence neural development, cognition and behaviour, with recent evidence that changes in behaviour alter gut microbiota composition, while modifications of the microbiome can induce depressive-like behaviours. Although an association between enteropathy and certain psychiatric conditions has long been recognized, it now appears that gut microbes represent direct mediators of psychopathology. Here, we examine roles of gut microbiome in shaping brain development and neurological function, and the mechanisms by which it can contribute to mental illness. Further, we discuss how the insight provided by this new and exciting field of research can inform care and provide a basis for the design of novel, microbiota-targeted, therapies.
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Affiliation(s)
- G B Rogers
- South Australian Health and Medical Research Institute, Infection and Immunity Theme, School of Medicine, Flinders University, Adelaide, SA, Australia
| | - D J Keating
- South Australian Health and Medical Research Institute, Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, SA, Australia
| | - R L Young
- South Australian Health and Medical Research Institute, Department of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - M-L Wong
- South Australian Health and Medical Research Institute, Mind and Brain Theme, and Flinders University, Adelaide, SA, Australia
| | - J Licinio
- South Australian Health and Medical Research Institute, Mind and Brain Theme, and Flinders University, Adelaide, SA, Australia
| | - S Wesselingh
- South Australian Health and Medical Research Institute, Infection and Immunity Theme, School of Medicine, Flinders University, Adelaide, SA, Australia
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Cvijanovic N, Isaacs NJ, Rayner CK, Feinle-Bisset C, Young RL, Little TJ. Duodenal fatty acid sensor and transporter expression following acute fat exposure in healthy lean humans. Clin Nutr 2016; 36:564-569. [PMID: 26926575 DOI: 10.1016/j.clnu.2016.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND & AIMS Free fatty acids (FFAs) and their derivatives are detected by G-protein coupled receptors (GPRs) on enteroendocrine cells, with specific transporters on enterocytes. It is unknown whether acute fat exposure affects FFA sensors/transporters, and whether this relates to hormone secretion and habitual fat intake. METHODS We studied 20 healthy participants (10M, 10F; BMI: 22 ± 1 kg/m2; age: 28 ± 2 years), after an overnight fast, on 2 separate days. On the first day, duodenal biopsies were collected endoscopically before, and after, a 30-min intraduodenal (ID) infusion of 10% Intralipid®, and relative transcript expression of FFA receptor 1 (FFAR1), FFA receptor 4 (FFAR4), GPR119 and the FFA transporter, cluster of differentiation-36 (CD36) was quantified from biopsies. On the second day, ID Intralipid® was infused for 120-min, and plasma concentrations of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) evaluated. Habitual dietary intake was assessed using food frequency questionnaires (FFQs). RESULTS ID Intralipid® increased expression of GPR119, but not FFAR1, FFAR4 and CD36, and stimulated CCK and GLP-1 secretion. Habitual polyunsaturated fatty acid (PUFA) consumption was negatively associated with basal GPR119 expression. CONCLUSIONS GPR119 is an early transcriptional responder to duodenal lipid in lean humans, although this response appeared reduced in individuals with high PUFA intake. These observations may have implications for downstream regulation of gut hormone secretion and appetite. This study was registered as a clinical trial with the Australia and New Zealand Clinical Trial Registry (Trial number: ACTRN12612000376842).
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Affiliation(s)
- Nada Cvijanovic
- University of Adelaide Discipline of Medicine, Adelaide, Australia; South Australian Health and Medical Research Institute, Adelaide, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Nicole J Isaacs
- University of Adelaide Discipline of Medicine, Adelaide, Australia; South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Christopher K Rayner
- University of Adelaide Discipline of Medicine, Adelaide, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia; Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Christine Feinle-Bisset
- University of Adelaide Discipline of Medicine, Adelaide, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Richard L Young
- University of Adelaide Discipline of Medicine, Adelaide, Australia; South Australian Health and Medical Research Institute, Adelaide, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Tanya J Little
- University of Adelaide Discipline of Medicine, Adelaide, Australia; NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
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33
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Zelkas L, Raghupathi R, Lumsden AL, Martin AM, Sun E, Spencer NJ, Young RL, Keating DJ. Serotonin-secreting enteroendocrine cells respond via diverse mechanisms to acute and chronic changes in glucose availability. Nutr Metab (Lond) 2015; 12:55. [PMID: 26673561 PMCID: PMC4678665 DOI: 10.1186/s12986-015-0051-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/09/2015] [Indexed: 01/11/2023] Open
Abstract
Background Enteroendocrine cells collectively constitute our largest endocrine tissue, with serotonin (5-HT) secreting enterochromaffin (EC) cells being the largest component (~50 %). This gut-derived 5-HT has multiple paracrine and endocrine roles. EC cells are thought to act as nutrient sensors and luminal glucose is the major absorbed form of carbohydrate in the gut and activates secretion in an array of cell types. It is unknown whether EC cells release 5-HT in response to glucose in primary EC cells. Furthermore, fasting augments 5-HT synthesis and release into the circulation. However, which nutrients cause fasting-induced synthesis of EC cell 5-HT is unknown. Here we examine the effects of acute and chronic changes in glucose availability on 5-HT release from intact tissue and single EC cells. Methods We utilised established approaches in our laboratories measuring 5-HT release in intact mouse colon with amperometry. We then examined single EC cells function using our published protocol in guinea-pig colon. Single cell Ca2+ imaging and amperometry were used with these cells. Real-time PCR was used along with amperometry, on primary EC cells cultured for 24 h in 5 or 25 mM glucose. Results We demonstrate that acute increases in glucose, at levels found in the gut lumen rather than in plasma, trigger 5-HT release from intact colon, and cause Ca2+ entry and 5-HT release in primary EC cells. Single cell amperometry demonstrates that high glucose increases the amount of 5-HT released from individual vesicles as they undergo exocytosis. Finally, 24 h incubation of EC cells in low glucose causes an increase in the transcription of the 5-HT synthesising enzyme Tph1 as well as increasing in 5-HT secretion in EC cells. Conclusions We demonstrate that primary EC cells respond to acute changes in glucose availability through increases in intracellular Ca2+ the activation of 5-HT secretion, but respond to chronic changes in glucose levels through the transcriptional regulation of Tph1 to alter 5-HT synthesis.
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Affiliation(s)
- Leah Zelkas
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia
| | - Ravi Raghupathi
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia ; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia
| | - Amanda L Lumsden
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia ; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia
| | - Alyce M Martin
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia ; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia
| | - Emily Sun
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia ; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia
| | - Nick J Spencer
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia
| | - Richard L Young
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia ; Discipline of Medicine, University of Adelaide, Adelaide, SA 5001 Australia
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Sturt Rd, Adelaide, SA 5042 Australia ; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5001 Australia
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Affiliation(s)
- Richard L Young
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia; Department of Medicine, University of Adelaide, Adelaide, Australia
| | - Amanda L Lumsden
- Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, Australia
| | - Damien J Keating
- South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia; Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, Australia
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Symonds EL, Peiris M, Page AJ, Chia B, Dogra H, Masding A, Galanakis V, Atiba M, Bulmer D, Young RL, Blackshaw LA. Mechanisms of activation of mouse and human enteroendocrine cells by nutrients. Gut 2015; 64:618-26. [PMID: 25015642 PMCID: PMC4392230 DOI: 10.1136/gutjnl-2014-306834] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Inhibition of food intake and glucose homeostasis are both promoted when nutrients stimulate enteroendocrine cells (EEC) to release gut hormones. Several specific nutrient receptors may be located on EEC that respond to dietary sugars, amino acids and fatty acids. Bypass surgery for obesity and type II diabetes works by shunting nutrients to the distal gut, where it increases activation of nutrient receptors and mediator release, but cellular mechanisms of activation are largely unknown. We determined which nutrient receptors are expressed in which gut regions and in which cells in mouse and human, how they are associated with different types of EEC, how they are activated leading to hormone and 5-HT release. DESIGN AND RESULTS mRNA expression of 17 nutrient receptors and EEC mediators was assessed by quantitative PCR and found throughout mouse and human gut epithelium. Many species similarities emerged, in particular the dense expression of several receptors in the distal gut. Immunolabelling showed specific colocalisation of receptors with EEC mediators PYY and GLP-1 (L-cells) or 5-HT (enterochromaffin cells). We exposed isolated proximal colonic mucosa to specific nutrients, which recruited signalling pathways within specific EEC extracellular receptor-regulated kinase (p-ERK) and calmodulin kinase II (pCAMKII), as shown by subsequent immunolabelling, and activated release of these mediators. Aromatic amino acids activated both pathways in mouse, but in humans they induced only pCAMKII, which was colocalised mainly with 5-HT expression. Activation was pertussis toxin-sensitive. Fatty acid (C12) potently activated p-ERK in human in all EEC types and evoked potent release of all three mediators. CONCLUSIONS Specific nutrient receptors associate with distinct activation pathways within EEC. These may provide discrete, complementary pharmacological targets for intervention in obesity and type II diabetes.
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Affiliation(s)
- Erin L Symonds
- Nerve-Gut Research Laboratory, Hanson Institute, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Madusha Peiris
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Amanda J Page
- Nerve-Gut Research Laboratory, Hanson Institute, Royal Adelaide Hospital, Adelaide, South Australia, Australia,Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Bridgette Chia
- Nerve-Gut Research Laboratory, Hanson Institute, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Harween Dogra
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Abigail Masding
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Vasileios Galanakis
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Michael Atiba
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - David Bulmer
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK
| | - Richard L Young
- Nerve-Gut Research Laboratory, Hanson Institute, Royal Adelaide Hospital, Adelaide, South Australia, Australia,Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - L Ashley Blackshaw
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary, University of London, London, UK,Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
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Nguyen NQ, Debreceni TL, Bambrick JE, Chia B, Wishart J, Deane AM, Rayner CK, Horowitz M, Young RL. Accelerated intestinal glucose absorption in morbidly obese humans: relationship to glucose transporters, incretin hormones, and glycemia. J Clin Endocrinol Metab 2015; 100:968-76. [PMID: 25423571 DOI: 10.1210/jc.2014-3144] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Intestinal glucose absorption is mediated by sodium-dependent glucose transporter 1 (SGLT-1) and glucose transporter 2 (GLUT2), which are linked to sweet taste receptor (STR) signaling and incretin responses. OBJECTIVE This study aimed to examine intestinal glucose absorption in morbidly obese humans and its relationship to the expression of STR and glucose transporters, glycemia, and incretin responses. DESIGN/SETTING/PARTICIPANTS Seventeen nondiabetic, morbidly obese subjects (body mass index [BMI], 48 ± 4 kg/m(2)) and 11 lean controls (BMI, 25 ± 1 kg/m(2)) underwent endoscopic duodenal biopsies before and after a 30-minute intraduodenal glucose infusion (30 g glucose and 3 g 3-O-methylglucose [3-OMG]). MAIN OUTCOME MEASURES Blood glucose and plasma concentrations of 3-OMG, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1), insulin, and glucagon were measured over 270 minutes. Expression of duodenal SGLT-1, GLUT2, and STR (T1R2) was quantified by PCR. RESULTS The increase in plasma 3-OMG (P < .001) and blood glucose (P < .0001) were greater in obese than lean subjects. Plasma 3-OMG correlated directly with blood glucose (r = 0.78, P < .01). In response to intraduodenal glucose, plasma GIP (P < .001), glucagon (P < .001), and insulin (P < .001) were higher, but GLP-1 (P < .001) was less in the obese compared with lean. Expression of SGLT-1 (P = .035), but not GLUT2 or T1R2, was higher in the obese, and related to peak plasma 3-OMG (r = 0.60, P = .01), GIP (r = 0.67, P = .003), and insulin (r = 0.58, P = .02). CONCLUSIONS In morbid obesity, proximal intestine glucose absorption is accelerated and related to increased SGLT-1 expression, leading to an incretin-glucagon profile promoting hyperinsulinemia and hyperglycemia. These findings are consistent with the concept that accelerated glucose absorption in the proximal gut underlies the foregut theory of obesity and type 2 diabetes.
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Affiliation(s)
- Nam Q Nguyen
- Department of Gastroenterology and Hepatology (N.Q.N., T.L.D., J.E.B., C.K.R.), Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia; Discipline of Medicine (N.Q.N., J.W., A.M.D., C.K.R., M.H., R.L.Y.), University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia; Nerve-Gut Research Laboratory (B.C., R.L.Y.), Hanson Institute, Adelaide, South Australia, 5000, Australia; and Intensive Care Unit (A.M.D.), Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia
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Reddi BA, Beltrame JF, Young RL, Wilson DP. Calcium desensitisation in late polymicrobial sepsis is associated with loss of vasopressor sensitivity in a murine model. Intensive Care Med Exp 2015. [PMID: 26215803 PMCID: PMC4512972 DOI: 10.1186/s40635-014-0036-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background Sepsis is characterised by diminished vasopressor responsiveness. Vasoconstriction depends upon a balance: Ca2+-dependent myosin light-chain kinase promotes and Ca2+-independent myosin light-chain phosphatase (MLCP) opposes vascular smooth muscle contraction. The enzyme Rho kinase (ROK) inhibits MLCP, favouring vasoconstriction. We tested the hypothesis that ROK-dependent MLCP inhibition was attenuated in late sepsis and associated with reduced contractile responses to certain vasopressor agents. Methods This is a prospective, controlled animal study. Sixteen-week-old C57/BL6 mice received laparotomy or laparotomy with caecal ligation and puncture (CLP). Antibiotics, fluids and analgesia were provided before sacrifice on day 5. Vasoconstriction of the femoral arteries to a range of stimuli was assessed using myography: (i) depolarisation with 87 mM K+ assessed voltage-gated Ca2+ channels (L-type, Cav1.2 Ca2+ channels (LTCC)), (ii) thromboxane A2 receptor activation assessed the activation state of the LTCC and ROK/MLCP axis, (iii) direct PKC activation (phorbol-dibutyrate (PDBu), 5 μM) assessed the PKC/CPI-17 axis independent of Ca2+ entry and (iv) α1-adrenoceptor stimulation with phenylephrine (10−8 to 10−4 M) and noradrenaline (10−8 to 10−4 M) assessed the sum of these pathways plus the role of the sarcoplasmic reticulum (SR). ROK-dependent MLCP activity was indexed by Western blot analysis of P[Thr855]MYPT. Parametric and non-parametric data were analysed using unpaired Student's t-tests and Mann-Whitney tests, respectively. Results ROK-dependent inhibition of MLCP activity was attenuated in both unstimulated (n = 6 to 7) and stimulated (n = 8 to 12) vessels from mice that had undergone CLP (p < 0.05). Vessels from CLP mice demonstrated reduced vasoconstriction to K+, thromboxane A2 receptor activation and PKC activation (n = 8 to 13; p < 0.05). α1-adrenergic responses were unchanged (n = 7 to 12). Conclusions In a murine model of sepsis, ROK-dependent inhibition of MLCP activity in vessels from septic mice was reduced. Responses to K+ depolarisation, thromboxane A2 receptor activation and PKC activation were diminished in vitro whilst α1-adrenergic responses remained intact. Inhibiting MLCP may present a novel therapeutic target to manage sepsis-induced vascular dysfunction.
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Affiliation(s)
- Benjamin Aj Reddi
- Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, 5000, Australia,
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Cvijanovic N, Isaacs NJ, Rayner CK, Feinle-Bisset C, Young RL, Little TJ. Pyloric motility and energy intake responses to intraduodenal fat in lean, overweight and obese humans. Obes Res Clin Pract 2014. [DOI: 10.1016/j.orcp.2014.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Little TJ, Isaacs NJ, Young RL, Ott R, Nguyen NQ, Rayner CK, Horowitz M, Feinle-Bisset C. Characterization of duodenal expression and localization of fatty acid-sensing receptors in humans: relationships with body mass index. Am J Physiol Gastrointest Liver Physiol 2014; 307:G958-67. [PMID: 25258406 DOI: 10.1152/ajpgi.00134.2014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fatty acids (FAs) stimulate the secretion of gastrointestinal hormones, including cholecystokinin (CCK) and glucagon like peptide-1 (GLP-1), which suppress energy intake. In obesity, gastrointestinal responses to FAs are attenuated. Recent studies have identified a key role for the FA-sensing receptors cluster of differentiation (CD)36, G protein-coupled receptor (GPR)40, GPR120, and GPR119 in mediating gastrointestinal hormone secretion. This study aimed to determine the expression and localization of these receptors in the duodenum of humans and to examine relationships with obesity. Duodenal mucosal biopsies were collected from nine lean [body mass index (BMI): 22 ± 1 kg/m2], six overweight (BMI: 28 ± 1 kg/m2), and seven obese (BMI: 49 ± 5 kg/m2) participants. Absolute levels of receptor transcripts were quantified using RT-PCR, while immunohistochemistry was used for localization. Transcripts were expressed in the duodenum of lean, overweight, and obese individuals with abundance of CD36>>GPR40>GPR120>GPR119. Expression levels of GPR120 (r = 0.46, P = 0.03) and CD36 (r = 0.69, P = 0.0004) were directly correlated with BMI. There was an inverse correlation between expression of GPR119 with BMI (r2 = 0.26, P = 0.016). Immunolabeling studies localized CD36 to the brush border membrane of the duodenal mucosa and GPR40, GPR120, and GPR119 to enteroendocrine cells. The number of cells immunolabeled with CCK (r = -0.54, P = 0.03) and GLP-1 (r = -0.49, P = 0.045) was inversely correlated with BMI, such that duodenal CCK and GLP-1 cell density decreased with increasing BMI. In conclusion, CD36, GPR40, GPR120, and GPR119 are expressed in the human duodenum. Transcript levels of duodenal FA receptors and enteroendocrine cell density are altered with increasing BMI, suggesting that these changes may underlie decreased gastrointestinal hormone responses to fat and impaired energy intake regulation in obesity.
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Affiliation(s)
- Tanya J Little
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and
| | - Nicole J Isaacs
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia
| | - Richard L Young
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and
| | - Raffael Ott
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia
| | - Nam Q Nguyen
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Michael Horowitz
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and
| | - Christine Feinle-Bisset
- University of Adelaide Discipline of Medicine, Adelaide, South Australia, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia; and
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Nguyen NQ, Debreceni TL, Bambrick JE, Chia B, Deane AM, Wittert G, Rayner CK, Horowitz M, Young RL. Upregulation of intestinal glucose transporters after Roux-en-Y gastric bypass to prevent carbohydrate malabsorption. Obesity (Silver Spring) 2014; 22:2164-71. [PMID: 24990218 DOI: 10.1002/oby.20829] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/23/2014] [Accepted: 06/13/2014] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To determine the effect of Roux-en-Y gastric bypass (RYGB) on the expression of intestinal sweet taste receptors (STRs), glucose transporters (GTs), glucose absorption, and glycemia. METHODS Intestinal biopsies were collected for mRNA expression of STR (T1R2) and GTs (SGLT-1 and GLUT2) from 11 non-diabetic RYGB, 13 non-diabetic obese, and 11 healthy subjects, at baseline and following a 30 min small intestinal (SI) glucose infusion (30 g/150 ml water with 3 g 3-O-methyl-d-glucopyranose (3-OMG)). Blood glucose, plasma 3-OMG, and insulin were measured for 270 min. RESULTS In RYGB patients, expression of both GTs was ∼2-fold higher at baseline and after glucose infusion than those of morbidly obese or healthy subjects (P < 0.001). STR expressions were comparable amongst the groups. Peak plasma 3-OMG in both RYGB (r = 0.69, P = 0.01) and obese (r = 0.72, P = 0.005) correlated with baseline expression of SGLT-1, as was the case with peak blood glucose in RYGB subjects (r = 0.69, P = 0.02). CONCLUSIONS The upregulated intestinal GTs in RYGB patients are associated with increased glucose absorption when glucose is delivered at a physiological rate, suggesting a molecular adaptation to prevent carbohydrate malabsorption from rapid intestinal transit after RYGB.
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Affiliation(s)
- Nam Q Nguyen
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, 5000, Australia; Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, 5000, Australia
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Abstract
Recent developments in the field of diabetes and obesity management have established the central role of the gut in glucose homeostasis; not only is the gut the primary absorptive site, but it also triggers neurohumoral feedback responses that regulate the pre- and post-absorptive phases of glucose metabolism. Structural and/or functional disorders of the intestine have the capacity to enhance (e.g.: diabetes) or inhibit (e.g.: short-gut syndrome, critical illness) glucose absorption, with potentially detrimental outcomes. In this review, we first describe the normal physiology of glucose absorption and outline the methods by which it can be quantified. Then we focus on the structural and functional changes in the small intestine associated with obesity, critical illness, short gut syndrome and other malabsorptive states, and particularly Type 2 diabetes, which can impact upon carbohydrate absorption and overall glucose homeostasis.
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Affiliation(s)
- Sony S Thazhath
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, SA, Australia
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Deane AM, Rayner CK, Keeshan A, Cvijanovic N, Marino Z, Nguyen NQ, Chia B, Summers MJ, Sim JA, van Beek T, Chapman MJ, Horowitz M, Young RL. The effects of critical illness on intestinal glucose sensing, transporters, and absorption. Crit Care Med 2014; 42:57-65. [PMID: 23963126 DOI: 10.1097/ccm.0b013e318298a8af] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Providing effective enteral nutrition is important during critical illness. In health, glucose is absorbed from the small intestine via sodium-dependent glucose transporter-1 and glucose transporter-2, which may both be regulated by intestinal sweet taste receptors. We evaluated the effect of critical illness on glucose absorption and expression of intestinal sodium-dependent glucose transporter-1, glucose transporter-2, and sweet taste receptors in humans and mice. DESIGN Prospective observational study in humans and mice. SETTING ICU and university-affiliated research laboratory. SUBJECTS Human subjects were 12 critically ill patients and 12 healthy controls. In the laboratory 16-week-old mice were studied. INTERVENTIONS Human subjects underwent endoscopy. Glucose (30 g) and 3-O-methylglucose (3 g), used to estimate glucose absorption, were infused intraduodenally over 30 minutes. Duodenal mucosa was biopsied before and after infusion. Mice were randomized to cecal ligation and puncture to model critical illness (n = 16) or sham laparotomy (control) (n = 8). At day 5, mice received glucose (100 mg) and 3-O-methylglucose (10 mg) infused intraduodenally prior to mucosal tissue collection. MEASUREMENTS AND MAIN RESULTS Quantitative polymerase chain reaction was performed to measure absolute (human) and relative levels of sodium-dependent glucose transporter-1, glucose transporter-2, and taste receptor type 1 member 2 (T1R2) transcripts. Blood samples were assayed for 3-O-methylglucose to estimate glucose absorption. Glucose absorption was three-fold lower in critically ill humans than in controls (p = 0.002) and reduced by a similar proportion in cecal ligation and puncture mice (p = 0.004). In critically ill patients, duodenal levels of sodium-dependent glucose transporter-1, glucose transporter-2, and T1R2 transcript were reduced 49% (p < 0.001), 50% (p = 0.009), and 85% (p = 0.007), whereas in the jejunum of cecal ligation and puncture mice sodium-dependent glucose transporter-1, glucose transporter-2, and T1R2 transcripts were reduced by 55% (p < 0.001), 50% (p = 0.002), and 69% (p = 0.004). CONCLUSIONS Critical illness is characterized by markedly diminished glucose absorption, associated with reduced intestinal expression of glucose transporters (sodium-dependent glucose transporter-1 and glucose transporter-2) and sweet taste receptor transcripts. These changes are paralleled in cecal ligation and puncture mice.
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Affiliation(s)
- Adam M Deane
- 1Discipline of Acute Care Medicine, University of Adelaide, North Terrace, Adelaide, South Australia, Australia. 2Intensive Care Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia. 3Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia. 4Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia. 5Discipline of Medicine, Nerve-Gut Research Laboratory, Level-1 Hanson Institute, Adelaide, South Australia, Australia
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Cvijanovic N, Isaacs NJ, Rayner CK, Feinle-Bisset C, Young RL, Little TJ. Intestinal regulation of fatty acid receptors in lean and overweight humans. Obes Res Clin Pract 2013. [DOI: 10.1016/j.orcp.2013.12.578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wu T, Rayner CK, Young RL, Horowitz M. Gut motility and enteroendocrine secretion. Curr Opin Pharmacol 2013; 13:928-34. [PMID: 24060702 DOI: 10.1016/j.coph.2013.09.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/16/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023]
Abstract
The motility of the gastrointestinal (GI) tract is modulated by complex neural and hormonal networks; the latter include gut peptides released from enteroendocrine cells during both the interdigestive and postprandial periods. Conversely, it is increasingly recognised that GI motility is an important determinant of gut hormone secretion, in that the transit of luminal contents influences the degree of nutrient stimulation of enteroendocrine cells in different gut regions, as well as the overall length of gut exposed to nutrient. Of particular interest is the relationship between gallbladder emptying and enteroendocrine secretion. The inter-relationships between GI motility and enteroendocrine secretion are central to blood glucose homeostasis, where an understanding is fundamental to the development of novel strategies for the management of diabetes mellitus.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Australia
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Wu T, Bound MJ, Standfield SD, Bellon M, Young RL, Jones KL, Horowitz M, Rayner CK. Artificial sweeteners have no effect on gastric emptying, glucagon-like peptide-1, or glycemia after oral glucose in healthy humans. Diabetes Care 2013; 36:e202-3. [PMID: 24265374 PMCID: PMC3836145 DOI: 10.2337/dc13-0958] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Tongzhi Wu
- Corresponding author: Christopher K. Rayner,
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Young RL, Bhatnagar R, Mason ZD, Benson AJ, Hooper CE, Clive AO, Zahan-Evans N, Morley AJ, Harvey JE, Medford ARL, Maskell NA. S78 Evalution of an ambulatory pleural service: costs and benefits: Abstract S78 Table 1. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.85] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Young RL, Chia B, Isaacs NJ, Ma J, Khoo J, Wu T, Horowitz M, Rayner CK. Disordered control of intestinal sweet taste receptor expression and glucose absorption in type 2 diabetes. Diabetes 2013; 62:3532-41. [PMID: 23761104 PMCID: PMC3781477 DOI: 10.2337/db13-0581] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We previously established that the intestinal sweet taste receptors (STRs), T1R2 and T1R3, were expressed in distinct epithelial cells in the human proximal intestine and that their transcript levels varied with glycemic status in patients with type 2 diabetes. Here we determined whether STR expression was 1) acutely regulated by changes in luminal and systemic glucose levels, 2) disordered in type 2 diabetes, and 3) linked to glucose absorption. Fourteen healthy subjects and 13 patients with type 2 diabetes were studied twice, at euglycemia (5.2 ± 0.2 mmol/L) or hyperglycemia (12.3 ± 0.2 mmol/L). Endoscopic biopsy specimens were collected from the duodenum at baseline and after a 30-min intraduodenal glucose infusion of 30 g/150 mL water plus 3 g 3-O-methylglucose (3-OMG). STR transcripts were quantified by RT-PCR, and plasma was assayed for 3-OMG concentration. Intestinal STR transcript levels at baseline were unaffected by acute variations in glycemia in healthy subjects and in type 2 diabetic patients. T1R2 transcript levels increased after luminal glucose infusion in both groups during euglycemia (+5.8 × 10(4) and +5.8 × 10(4) copies, respectively) but decreased in healthy subjects during hyperglycemia (-1.4 × 10(4) copies). T1R2 levels increased significantly in type 2 diabetic patients under the same conditions (+6.9 × 10(5) copies). Plasma 3-OMG concentrations were significantly higher in type 2 diabetic patients than in healthy control subjects during acute hyperglycemia. Intestinal T1R2 expression is reciprocally regulated by luminal glucose in health according to glycemic status but is disordered in type 2 diabetes during acute hyperglycemia. This defect may enhance glucose absorption in type 2 diabetic patients and exacerbate postprandial hyperglycemia.
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Affiliation(s)
- Richard L. Young
- Nerve-Gut Research Laboratory, University of Adelaide, Adelaide, South Australia, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Corresponding author: Richard L. Young,
| | - Bridgette Chia
- Nerve-Gut Research Laboratory, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Nicole J. Isaacs
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Jing Ma
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Department of Endocrinology and Metabolism, Shanghai Renji Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Joan Khoo
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Department of Endocrinology, Changi General Hospital, Singapore
| | - Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher K. Rayner
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Harrington AM, Brierley SM, Isaacs NJ, Young RL, Blackshaw LA. Identifying spinal sensory pathways activated by noxious esophageal acid. Neurogastroenterol Motil 2013; 25:e660-8. [PMID: 23848546 DOI: 10.1111/nmo.12180] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/17/2013] [Accepted: 06/11/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND The transient receptor potential vanilloid 1 (TRPV1) channel is critical for spinal afferent signaling of burning pain throughout the body. Such pain frequently originates from the esophagus, following acid reflux. The contribution of TRPV1 to spinal nociceptor signaling from the esophagus remains unclear. We aimed to identify the spinal afferent pathways that convey nociceptive signaling from the esophagus, specifically those sensitive to acid, and the extent to which TRPV1 contributes. METHODS Acid/pepsin (150 mM HCl/1 mg mL(-1) pepsin) or saline/pepsin was perfused into the esophageal lumen of anesthetized wild-type and TRPV1 null mice over 20 min, followed by atraumatic perfuse fixation and removal of the cervical and thoracic spinal cord and dorsal root ganglia (DRG). To identify neurons responsive to esophageal perfusate, immunolabeling for neuronal activation marker phosphorylated extracellular receptor-regulated kinase (pERK) was used. Labeling for calcitonin gene-related peptide (CGRP) and isolectin B4 (IB4) was then used to characterize responsive neurons. KEY RESULTS Esophageal acid/pepsin perfusion significantly increased the number of pERK-immunoreactive (IR) neurons in the DRG and the cervical and thoracic spinal cord dorsal horn (DH) relative to saline/pepsin (DRG P < 0.01; cervical DH P < 0.05 and thoracic DH P < 0.005). The number of pERK-IR neurons following acid perfusion was significantly attenuated in TRPV1 -/- mice (DH P < 0.05 and DRG P < 0.05). CONCLUSIONS & INFERENCES This study has identified populations of spinal afferent DRG neurons and DH neurons involved in signaling of noxious acid from the esophagus. There is a major contribution of TRPV1 to signaling within these pathways.
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Affiliation(s)
- A M Harrington
- Nerve-Gut Research Laboratory, Discipline of Medicine, Faculty of Health Sciences, The University of Adelaide, Adelaide, South Australia, Australia; Department of Gastroenterology and Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Kentish SJ, O'Donnell TA, Isaacs NJ, Young RL, Li H, Harrington AM, Brierley SM, Wittert GA, Blackshaw LA, Page AJ. Gastric vagal afferent modulation by leptin is influenced by food intake status. J Physiol 2012; 591:1921-34. [PMID: 23266933 DOI: 10.1113/jphysiol.2012.247577] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Energy intake is strongly influenced by vagal afferent signals from the stomach, and is also modulated by leptin. Leptin may be secreted from gastric epithelial cells, so we aimed to determine the direct effect of leptin on gastric vagal afferents under different feeding conditions. Female C57BL/6 mice were fed standard laboratory diet, high-fat diet or were food restricted. The expression of leptin receptor (Lep-R) and its signal transduction molecules in vagal afferents was determined by retrograde tracing and reverse-transcription polymerase chain reaction, and the relationship between leptin-immunopositive cells and gastric vagal afferent endings determined by anterograde tracing and leptin immunohistochemistry. An in vitro preparation was used to determine the functional effects of leptin on gastric vagal afferents and the second messenger pathways involved. Leptin potentiated vagal mucosal afferent responses to tactile stimuli, and epithelial cells expressing leptin were found close to vagal mucosal endings. After fasting or diet-induced obesity, potentiation of mucosal afferents by leptin was lost and Lep-R expression reduced in the cell bodies of gastric mucosal afferents. These effects in diet-induced obese mice were accompanied by a reduction in anatomical vagal innervation of the gastric mucosa. In striking contrast, after fasting or diet-induced obesity, leptin actually inhibited responses to distension in tension receptors. The inhibitory effect on gastric tension receptors was mediated through phosphatidylinositol 3-kinase-dependent activation of large-conductance calcium-activated potassium channels. The excitatory effect of leptin on gastric mucosal vagal afferents was mediated by phospholipase C-dependent activation of canonical transient receptor potential channels. These data suggest the effect of leptin on gastric vagal afferent excitability is dynamic and related to the feeding state. Paradoxically, in obesity, leptin may reduce responses to gastric distension following food intake.
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Affiliation(s)
- Stephen J Kentish
- Nerve-Gut Research Laboratory, Room 1-216-H, Level 1, Hanson Institute, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
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Page AJ, Symonds E, Peiris M, Blackshaw LA, Young RL. Peripheral neural targets in obesity. Br J Pharmacol 2012; 166:1537-58. [PMID: 22432806 PMCID: PMC3419899 DOI: 10.1111/j.1476-5381.2012.01951.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 02/20/2012] [Accepted: 02/22/2012] [Indexed: 12/15/2022] Open
Abstract
Interest in pharmacological treatments for obesity that act in the brain to reduce appetite has increased exponentially over recent years, but failures of clinical trials and withdrawals due to adverse effects have so far precluded any success. Treatments that do not act within the brain are, in contrast, a neglected area of research and development. This is despite the fact that a vast wealth of molecular mechanisms exists within the gut epithelium and vagal afferent system that could be manipulated to increase satiety. Here we discuss mechano- and chemosensory pathways from the gut involved in appetite suppression, and distinguish between gastric and intestinal vagal afferent pathways in terms of their basic physiology and activation by enteroendocrine factors. Gastric bypass surgery makes use of this system by exposing areas of the intestine to greater nutrient loads resulting in greater satiety hormone release and reduced food intake. A non-surgical approach to this system is preferable for many reasons. This review details where the opportunities may lie for such approaches by describing nutrient-sensing mechanisms throughout the gastrointestinal tract.
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Affiliation(s)
- Amanda J Page
- Nerve-Gut Research Laboratory, Discipline of Medicine, South Australia, Australia
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