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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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2
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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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3
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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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4
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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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5
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Sposato LA, Lam Y, Karapetis C, Vatandoust S, Roy A, Hakendorf P, Dwyer A, de Fontgalland D, Hollington P, Wattchow D. Observation of "complete clinical response" in rectal cancer after neoadjuvant chemoradiation: The Flinders experience. Asia Pac J Clin Oncol 2018; 14:439-445. [PMID: 29932278 DOI: 10.1111/ajco.12993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 11/04/2017] [Accepted: 04/29/2018] [Indexed: 01/17/2023]
Abstract
AIM Observation with close follow-up ("watch and wait") is a recognized treatment option in patients who achieve a complete clinical response to long course chemoradiotherapy. This review of a prospective database aims to evaluate the clinical outcomes among patients with a complete clinical response managed with observation. METHODS A prospective study of 32 patients who achieved a complete clinical response was undertaken. The primary outcomes measured were overall and recurrence-free survival, and rate of organ preservation in patients who deferred immediate surgery. RESULTS Seven patients developed local regrowth over a median follow-up period of 38 months (range, 9-91 months). Median time to detection was 12 months. All seven underwent salvage surgery with complete surgical clearance. One patient developed combined local and systemic recurrence following a low anterior resection. Organ preservation was possible in 25 (78%) patients who sustained a complete clinical response with no evidence of local regrowth or disease recurrence. Among the patients who sustained a complete response, two developed isolated systemic disease. Overall and recurrence-free survival was 95.7% and 87.0%, respectively. CONCLUSION The majority of patients with rectal cancer who achieved a complete clinical response after chemoradiotherapy and managed with a "watch and wait" approach preserved their rectum and did not develop cancer relapse. Salvage surgery was achieved in all patients who developed local regrowth. The study supports a period of observation in rectal cancer patients who achieve a complete clinical response.
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Affiliation(s)
- Luigi A Sposato
- Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Yick Lam
- Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Chris Karapetis
- Department of Medical Oncology, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Sina Vatandoust
- Department of Medical Oncology, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Amitesh Roy
- Department of Medical Oncology, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Paul Hakendorf
- Department of Epidemiology, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Andrew Dwyer
- Department of Radiology, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Dayan de Fontgalland
- Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
| | - David Wattchow
- Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia
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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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7
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Hu M, Wattchow D, de Fontgalland D. From ancient to avant-garde: a review of traditional and modern multimodal approaches to surgical anatomy education. ANZ J Surg 2017; 88:146-151. [PMID: 28922705 DOI: 10.1111/ans.14189] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [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: 05/31/2017] [Revised: 06/27/2017] [Accepted: 07/14/2017] [Indexed: 11/28/2022]
Abstract
The landscape of surgical anatomy education is progressively changing. Traditional methods, such as cadaveric dissection and didacticism are being increasingly phased out in undergraduate courses for multimodal approaches incorporating problem-based learning, radiology and computer-based simulations. Although effective at clinically contextualizing and integrating anatomical information, these approaches may be a poor substitute for fostering a grasp of foundational 'pure' anatomy. Dissection is ideal for this purpose and hence remains the cornerstone of anatomical education. However, novel methods and technological advancements continually give way to adjuncts such as cadaveric surgery, three-dimensional printing, virtual simulation and live surgical streaming, which have demonstrated significant efficacy alone or alongside dissection. Therefore, although divergent paradigms of 'new versus old' approaches have engulfed and divided the community, educators should seek to integrate the ancient and avant-garde to comprehensively satisfy all of the modern anatomy learner's educational needs.
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Affiliation(s)
- Minhao Hu
- School of Medicine, Flinders University, Adelaide, South Australia, Australia
| | - David Wattchow
- Department of Surgery, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Department of Surgery, Flinders Medical Centre, Adelaide, South Australia, Australia
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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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Leow S, Voyvodic F, Murphy E, de Fontgalland D. Unprecedented complication of biologic mesh use in ventral rectopexy. ANZ J Surg 2017; 88:E811-E812. [PMID: 28239943 DOI: 10.1111/ans.13912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/18/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Sean Leow
- Division of Surgery and Perioperative Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Frank Voyvodic
- Benson Radiology, Adelaide, South Australia, Australia.,Division of Medical Imaging, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Elizabeth Murphy
- Colorectal Unit, Lyell McEwin Hospital, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Division of Surgery and Perioperative Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
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Leow S, Rodgers N, de Fontgalland D. Endoscopic capsule retention: a complication with an underappreciated cause. ANZ J Surg 2016; 88:649-651. [PMID: 26989889 DOI: 10.1111/ans.13459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Sean Leow
- Division of Surgery and Perioperative Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Nick Rodgers
- Adelaide Pathology Partners, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Division of Surgery and Perioperative Medicine, Flinders Medical Centre, Adelaide, South Australia, Australia
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