1
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Lewis GF, Mulvihill EE. The Complexities of Intestinal Lipoprotein Production in Insulin Resistance and Diabetes: Revisiting a 2010 Diabetes Classic by Pavlic et al. Diabetes 2024; 73:335-337. [PMID: 38377446 DOI: 10.2337/dbi23-0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 02/22/2024]
Affiliation(s)
- Gary F Lewis
- Department of Medicine and Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology and Metabolism, University of Toronto, Toronto, Ontario, Canada
| | - Erin E Mulvihill
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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2
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Majumdar SK. Triglyceride Clearance in Hypertriglyceridemic Pancreatitis: Time Course and Its Implications for Management. Endocr Pract 2023; 29:971-979. [PMID: 37714331 DOI: 10.1016/j.eprac.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/25/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023]
Abstract
OBJECTIVE To characterize the time course of triglyceride (Tg) lowering in hypertriglyceridemic (HTg) pancreatitis according to the initial Tg values, causes, and interventions. METHODS Patients hospitalized from October 2013 through December of 2018 with a diagnosis of pancreatitis associated with HTg (Tg level, ≥500 mg/dL), in the absence of other causes, were identified by medical record review. Tg lowering was retrospectively assessed for differences in relation to the initial Tg values, use of intravenous insulin, ethanol-associated versus nonethanol-associated causes, and time to Tg values of <500 versus <1000 mg/dL. RESULTS Sixty-six cases were identified, and 45 had multiple measurements for time-course evaluation. Those with initial Tg values of <4000 mg/dL achieved Tg levels of <1000 mg/dL in <3 days, whereas 18.8% with higher values took 5-9 days. Insulin therapy was associated with a longer duration of HTg, whereas ethanol was associated with a shorter duration. Tg clearance in ethanol-associated HTg appeared independent of insulin treatment. Time to Tg levels of <500 mg/dL versus <1000 mg/dL was significantly longer when the initial Tg levels were >2000 mg/dL. CONCLUSION A threshold of 4000 mg/dL for the initial Tg levels in HTg pancreatitis appears to separate patients who are likely to achieve Tg levels of <1000 mg/dL in <3 versus >3 days, independent of cause or treatment. Insulin therapy is appropriate for patients with hyperglycemia but appears unnecessary for those with isolated ethanol-associated HTg. A threshold Tg level of <1000 mg/dL appears more practical than that of <500 mg/dL for resuming nutritional intake.
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Affiliation(s)
- Sachin K Majumdar
- Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut; Departments of Endocrinology and Internal Medicine, Bridgeport Hospital, Yale New Haven Health System, Bridgeport, Connecticut.
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3
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Fourati S, Hamon A, Daclat R, Salem JE, Peoc’h K, Le Beyec J, Joly F, Lacorte JM. Circulating Apolipoprotein B-48 as a Biomarker of Parenteral Nutrition Dependence in Adult Patients with Short Bowel Syndrome. Nutrients 2023; 15:3982. [PMID: 37764766 PMCID: PMC10536633 DOI: 10.3390/nu15183982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Short bowel syndrome (SBS) is a rare but serious condition that may lead to chronic intestinal failure. Citrulline concentrations are currently used to reflect the residual intestinal mass in patients with SBS, although this method has several limitations. In a cohort of patients with SBS, we quantified apolipoprotein B-48 (ApoB-48), which is exclusively synthesized by enterocytes and secreted associated with dietary lipids and investigated the relationship between ApoB-48 and clinical and biological data as well as PN dependence. A total of 51 adult patients were included, 36 of whom were PN-dependent. We found a robust positive correlation between circulating ApoB-48 and residual small bowel length, which was also found in the subgroup of patients with jejunocolic anastomosis. Fasting ApoB-48 levels were significantly lower in PN-dependent patients than in PN-weaned patients and negatively correlated with parenteral nutrition dependence. Our results suggest that ApoB-48 could be proposed as a marker of intestinal absorptive function and could be an interesting follow-up marker in patients with SBS.
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Affiliation(s)
- Salma Fourati
- Service de Biochimie Endocrinienne et Oncologique, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, UMR-S 1149 Centre de Recherche sur l’Inflammation Inserm, Paris Cité University, 75013 Paris, France
| | - Annick Hamon
- Department of Gastroenterology, IBD and Nutrition Support, CRMR MarDi, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, 92110 Clichy, France
| | - Rita Daclat
- UMR_S1166, Research Institute of Cardiovascular Disease, Metabolism and Nutrition Inserm, Pitié-Salpêtrière Hospital, Sorbonne University, 75013 Paris, France
| | - Joe-Elie Salem
- Department of Pharmacology and Clinical Investigation Centre (CIC-1901), Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Sorbonne University, INSERM, 75013 Paris, France
| | - Katell Peoc’h
- Department of Biochemistry, CRI INSERM UMR1149, HUPNVS, Assistance Publique-Hôpitaux de Paris, Paris Cité University, 75018 Paris, France
| | - Johanne Le Beyec
- Service de Biochimie Endocrinienne et Oncologique, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, UMR-S 1149 Centre de Recherche sur l’Inflammation Inserm, Sorbonne University, 75013 Paris, France;
| | - Francisca Joly
- Department of Gastroenterology, IBD and Nutrition Support, CRMR MarDi, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, 92110 Clichy, UMR-S 1149 Centre de Recherche sur l’Inflammation Inserm, Université Paris Cité, 75018 Paris, France;
| | - Jean-Marc Lacorte
- Service de Biochimie Endocrinienne et Oncologique, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Research Unit on Cardiovascular and Metabolic Disease, UMR ICAN, Sorbonne University, Inserm, 75013 Paris, France;
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4
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Abstract
Postprandial hyperlipidaemia is an important feature of diabetic dyslipidaemia and plays an important role in the development of cardiovascular disease in individuals with type 2 diabetes. Postprandial hyperlipidaemia in type 2 diabetes is secondary to increased chylomicron production by the enterocytes and delayed catabolism of chylomicrons and chylomicron remnants. Insulin and some intestinal hormones (e.g. glucagon-like peptide-1 [GLP-1]) influence intestinal lipid metabolism. In individuals with type 2 diabetes, insulin resistance and possibly reduced GLP-1 secretion are involved in the pathophysiology of postprandial hyperlipidaemia. Several factors are involved in the overproduction of chylomicrons: (1) increased expression of microsomal triglyceride transfer protein, which is a key enzyme in chylomicron synthesis; (2) higher stability and availability of apolipoprotein B-48; and (3) increased de novo lipogenesis. Individuals with type 2 diabetes present with disorders of cholesterol metabolism in the enterocytes with reduced absorption and increased synthesis. The increased production of chylomicrons in type 2 diabetes is also associated with a reduction in their catabolism, mostly because of a reduction in activity of lipoprotein lipase. Modification of the microbiota, which is observed in type 2 diabetes, may also generate disorders of intestinal lipid metabolism, but human data remain limited. Some glucose-lowering treatments significantly influence intestinal lipid absorption and transport. Postprandial hyperlipidaemia is reduced by metformin, pioglitazone, alpha-glucosidase inhibitors, dipeptidyl peptidase 4 inhibitors and GLP-1 agonists. The most pronounced effect is observed with GLP-1 agonists, which reduce chylomicron production significantly in individuals with type 2 diabetes and have a direct effect on the intestine by reducing the expression of genes involved in intestinal lipoprotein metabolism. The effect of sodium-glucose cotransporter 2 inhibitors on intestinal lipid metabolism needs to be clarified.
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Affiliation(s)
- Bruno Vergès
- Endocrinology-Diabetology Department, University-Hospital, Dijon, France.
- Inserm UMR 1231, Medical School, University of Burgundy-Franche Comté, Dijon, France.
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5
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Cook JR, Kohan AB, Haeusler RA. An Updated Perspective on the Dual-Track Model of Enterocyte Fat Metabolism. J Lipid Res 2022; 63:100278. [PMID: 36100090 PMCID: PMC9593242 DOI: 10.1016/j.jlr.2022.100278] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/08/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023] Open
Abstract
The small intestinal epithelium has classically been envisioned as a conduit for nutrient absorption, but appreciation is growing for a larger and more dynamic role for enterocytes in lipid metabolism. Considerable gaps remain in our knowledge of this physiology, but it appears that the enterocyte's structural polarization dictates its behavior in fat partitioning, treating fat differently based on its absorption across the apical versus the basolateral membrane. In this review, we synthesize existing data and thought on this dual-track model of enterocyte fat metabolism through the lens of human integrative physiology. The apical track includes the canonical pathway of dietary lipid absorption across the apical brush-border membrane, leading to packaging and secretion of those lipids as chylomicrons. However, this track also reserves a portion of dietary lipid within cytoplasmic lipid droplets for later uses, including the "second-meal effect," which remains poorly understood. At the same time, the enterocyte takes up circulating fats across the basolateral membrane by mechanisms that may include receptor-mediated import of triglyceride-rich lipoproteins or their remnants, local hydrolysis and internalization of free fatty acids, or enterocyte de novo lipogenesis using basolaterally absorbed substrates. The ultimate destinations of basolateral-track fat may include fatty acid oxidation, structural lipid synthesis, storage in cytoplasmic lipid droplets, or ultimate resecretion, although the regulation and purposes of this basolateral track remain mysterious. We propose that the enterocyte integrates lipid flux along both of these tracks in order to calibrate its overall program of lipid metabolism.
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Affiliation(s)
- Joshua R. Cook
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Alison B. Kohan
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rebecca A. Haeusler
- Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA,Department of Pathology and Cell Biology; Columbia University College of Physicians and Surgeons, New York, NY, USA,For correspondence: Rebecca A. Haeusler
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6
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Hoffman S, Alvares D, Adeli K. GLP-1 attenuates intestinal fat absorption and chylomicron production via vagal afferent nerves originating in the portal vein. Mol Metab 2022; 65:101590. [PMID: 36067913 PMCID: PMC9486018 DOI: 10.1016/j.molmet.2022.101590] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/22/2022] [Accepted: 09/01/2022] [Indexed: 12/04/2022] Open
Abstract
Background/Objective GLP-1R agonists have been shown to reduce fasting and postprandial plasma lipids, both of which are independent risk factors for the development of cardiovascular disease. However, how endogenous GLP-1 – which is rapidly degraded – modulates intestinal and hepatic lipid metabolism is less clear. A vagal gut-brain-axis originating in the portal vein has been proposed as a possible mechanism for GLP-1’s anti-lipemic effects. Here we sought to examine the relationship between vagal GLP-1 signalling and intestinal lipid absorption and lipoprotein production. Methods Syrian golden hamsters or C57BL/6 mice received portal vein injections of GLP-1(7-36), and postprandial and fasting plasma TG, TRL TG, or VLDL TG were examined. These experiments were repeated during sympathetic blockade, and under a variety of pharmacological or surgical deafferentation techniques. In addition, hamsters received nodose ganglia injections of a GLP-1R agonist or antagonist to further probe the vagal pathway. Peripheral studies were repeated in a novel GLP-1R KO hamster model and in our diet-induced hamster models of insulin resistance. Results GLP-1(7-36) site-specifically reduced postprandial and fasting plasma lipids in both hamsters and mice. These inhibitory effects of GLP-1 were investigated via pharmacological and surgical denervation experiments and found to be dependent on intact afferent vagal signalling cascades and efferent changes in sympathetic tone. Furthermore, GLP-1R agonism in the nodose ganglia resulted in markedly reduced postprandial plasma TG and TRL TG, and fasting VLDL TG and this nodose GLP-1R activity was essential for portal GLP-1s effect. Notably, portal and nodose ganglia GLP-1 effects were lost in GLP-1R KO hamsters and following diet-induced insulin resistance. Conclusion Our data demonstrates for the first time that portal GLP-1 modulates postprandial and fasting lipids via a complex vagal gut–brain–liver axis. Importantly, loss or interference with this signalling axis via surgical, pharmacological, or dietary intervention resulted in the loss of portal GLP-1s anti-lipemic effects. This supports emerging evidence that native GLP-1 works primarily through a vagal neuroendocrine mechanism.
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Affiliation(s)
- Simon Hoffman
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
| | - Danielle Alvares
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
| | - Khosrow Adeli
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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7
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Ghanem M, Lewis GF, Xiao C. Recent advances in cytoplasmic lipid droplet metabolism in intestinal enterocyte. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159197. [PMID: 35820577 DOI: 10.1016/j.bbalip.2022.159197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
Processing of dietary fats in the intestine is a highly regulated process that influences whole-body energy homeostasis and multiple physiological functions. Dysregulated lipid handling in the intestine leads to dyslipidemia and atherosclerotic cardiovascular disease. In intestinal enterocytes, lipids are incorporated into lipoproteins and cytoplasmic lipid droplets (CLDs). Lipoprotein synthesis and CLD metabolism are inter-connected pathways with multiple points of regulation. This review aims to highlight recent advances in the regulatory mechanisms of lipid processing in the enterocyte, with particular focus on CLDs. In-depth understanding of the regulation of lipid metabolism in the enterocyte may help identify therapeutic targets for the treatment and prevention of metabolic disorders.
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Affiliation(s)
- Murooj Ghanem
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, and University Health Network, Toronto, ON, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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8
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Borén J, Taskinen MR, Björnson E, Packard CJ. Metabolism of triglyceride-rich lipoproteins in health and dyslipidaemia. Nat Rev Cardiol 2022; 19:577-592. [PMID: 35318466 DOI: 10.1038/s41569-022-00676-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/02/2022] [Indexed: 02/07/2023]
Abstract
Accumulating evidence points to the causal role of triglyceride-rich lipoproteins and their cholesterol-enriched remnants in atherogenesis. Genetic studies in particular have not only revealed a relationship between plasma triglyceride levels and the risk of atherosclerotic cardiovascular disease, but have also identified key proteins responsible for the regulation of triglyceride transport. Kinetic studies in humans using stable isotope tracers have been especially useful in delineating the function of these proteins and revealing the hitherto unappreciated complexity of triglyceride-rich lipoprotein metabolism. Given that triglyceride is an essential energy source for mammals, triglyceride transport is regulated by numerous mechanisms that balance availability with the energy demands of the body. Ongoing investigations are focused on determining the consequences of dysregulation as a result of either dietary imprudence or genetic variation that increases the risk of atherosclerosis and pancreatitis. The identification of molecular control mechanisms involved in triglyceride metabolism has laid the groundwork for a 'precision-medicine' approach to therapy. Novel pharmacological agents under development have specific molecular targets within a regulatory framework, and their deployment heralds a new era in lipid-lowering-mediated prevention of disease. In this Review, we outline what is known about the dysregulation of triglyceride transport in human hypertriglyceridaemia.
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Affiliation(s)
- Jan Borén
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden.
| | - Marja-Riitta Taskinen
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Elias Björnson
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Chris J Packard
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
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9
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Semova I, Levenson AE, Krawczyk J, Bullock K, Gearing ME, Ling AV, Williams KA, Miao J, Adamson SS, Shin DJ, Chahar S, Graham MJ, Crooke RM, Hagey LR, Vicent D, de Ferranti SD, Kidambi S, Clish CB, Biddinger SB. Insulin Prevents Hypercholesterolemia by Suppressing 12a-Hydroxylated Bile Acid Production. Circulation 2022; 145:969-982. [PMID: 35193378 PMCID: PMC9365453 DOI: 10.1161/circulationaha.120.045373] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: The risk of cardiovascular disease in type 1 diabetes remains extremely high, despite marked advances in blood glucose control and even the widespread use of cholesterol synthesis inhibitors. Thus, a deeper understanding of insulin regulation of cholesterol metabolism, and its disruption in type 1 diabetes, could reveal better treatment strategies. Methods: To define the mechanisms by which insulin controls plasma cholesterol levels, we knocked down the insulin receptor, FoxO1, and the key bile acid synthesis enzyme, CYP8B1. We measured bile acid composition, cholesterol absorption, and plasma cholesterol. In parallel, we measured markers of cholesterol absorption and synthesis in humans with type 1 diabetes treated with ezetimibe and statins in a double-blind crossover study. Results: Mice with hepatic deletion of the insulin receptor showed marked increases in 12α-hydroxylated bile acids (12HBAs), cholesterol absorption, and plasma cholesterol. This phenotype was entirely reversed by hepatic deletion of FoxO1. FoxO1 is inhibited by insulin, and required for the production of 12HBAs, which promote intestinal cholesterol absorption and suppress hepatic cholesterol synthesis. Knockdown of Cyp8b1 normalized 12HBA levels and completely prevented hypercholesterolemia in mice with hepatic deletion of the insulin receptor (n=5-30) as well as mouse models of type 1 diabetes (n=5-22). In parallel, the cholesterol absorption inhibitor, ezetimibe, normalized cholesterol absorption and LDL-cholesterol in patients with type 1 diabetes as well as, or better than, the cholesterol synthesis inhibitor, simvastatin (n=20). Conclusions: Insulin, by inhibiting FoxO1 in the liver, reduces 12HBAs, cholesterol absorption, and plasma cholesterol levels. Thus, type 1 diabetes leads to a unique set of derangements in cholesterol metabolism, with increased absorption rather than synthesis. These derangements are reversed by ezetimibe, but not statins, which are currently the first line of lipid-lowering treatment in type 1 diabetes. Taken together, these data suggest that a personalized approach to lipid lowering in type 1 diabetes may be more effective and highlight the need for further studies specifically in this group of patients.
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Affiliation(s)
- Ivana Semova
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Amy E Levenson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Joanna Krawczyk
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | - Mary E Gearing
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Alisha V Ling
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Kathryn A Williams
- Biostatistics and Research Design Center, ICCTR, Boston Children's Hospital, Boston, MA
| | - Ji Miao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Stuart S Adamson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Dong-Ju Shin
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Satyapal Chahar
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | | | - Lee R Hagey
- Department of Medicine, University of California, San Diego, CA
| | - David Vicent
- Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - Sarah D de Ferranti
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Srividya Kidambi
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
| | | | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
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Morrow NM, Trzaskalski NA, Hanson AA, Fadzeyeva E, Telford DE, Chhoker SS, Sutherland BG, Edwards JY, Huff MW, Mulvihill EE. Nobiletin Prevents High-Fat Diet-Induced Dysregulation of Intestinal Lipid Metabolism and Attenuates Postprandial Lipemia. Arterioscler Thromb Vasc Biol 2022; 42:127-144. [PMID: 34911361 DOI: 10.1161/atvbaha.121.316896] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Nobiletin is a dietary flavonoid that improves insulin resistance and atherosclerosis in mice with metabolic dysfunction. Dysregulation of intestinal lipoprotein metabolism contributes to atherogenesis. The objective of the study was to determine if nobiletin targets the intestine to improve metabolic dysregulation in both male and female mice. Approach and Results: Triglyceride-rich lipoprotein (TRL) secretion, intracellular triglyceride kinetics, and intestinal morphology were determined in male and female LDL (low-density lipoprotein) receptor knockout (Ldlr-/-), and male wild-type mice fed a standard laboratory diet or high-fat, high-cholesterol (HFHC) diet ± nobiletin using an olive oil gavage, radiotracers, and electron microscopy. Nobiletin attenuated postprandial TRL levels in plasma and enhanced TRL clearance. Nobiletin reduced fasting jejunal triglyceride accumulation through accelerated TRL secretion and lower jejunal fatty acid synthesis with no impact on fatty acid oxidation. Fasting-refeeding experiments revealed that nobiletin led to higher levels of phosphorylated AKT (protein kinase B) and FoxO1 (forkhead box O1) and normal Srebf1c expression indicating increased insulin sensitivity. Intestinal length and weight were diminished by HFHC feeding and restored by nobiletin. Both fasting and postprandial plasma GLP-1 (glucagon-like peptide-1; and likely GLP-2) were elevated in response to nobiletin. Treatment with a GLP-2 receptor antagonist, GLP-2(3-33), reduced villus length in HFHC-fed mice but did not impact TRL secretion in any diet group. In contrast to males, nobiletin did not improve postprandial lipid parameters in female mice. CONCLUSIONS Nobiletin opposed the effects of the HFHC diet by normalizing intestinal de novo lipogenesis through improved insulin sensitivity. Nobiletin prevents postprandial lipemia because the enhanced TRL clearance more than compensates for increased TRL secretion.
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Affiliation(s)
- Nadya M Morrow
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Natasha A Trzaskalski
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Antonio A Hanson
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Evgenia Fadzeyeva
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
| | - Dawn E Telford
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Sanjiv S Chhoker
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
| | - Brian G Sutherland
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Jane Y Edwards
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Murray W Huff
- Molecular Medicine, Robarts Research Institute (N.M.M., D.E.T., S.S.C., B.G.S., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
- Department of Biochemistry (N.M.M., S.S.C., M.W.H.), The University of Western Ontario, London, Canada
- Department of Medicine (D.E.T., J.Y.E., M.W.H.), The University of Western Ontario, London, Canada
| | - Erin E Mulvihill
- The University of Ottawa Heart Institute, Ontario, Canada (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
- Centre for Infection, Immunity and Inflammation, Ottawa, Ontario, Canada (E.E.M)
- Montreal Diabetes Research Group, Montreal, Quebec, Canada (E.E.M)
- Department of Biochemistry, Microbiology and Immunology, The University of Ottawa, Faculty of Medicine, ON (N.M.M., N.A.T., A.A.H., E.F., E.E.M.)
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11
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Stahel P, Xiao C, Nahmias A, Tian L, Lewis GF. Multi-organ Coordination of Lipoprotein Secretion by Hormones, Nutrients and Neural Networks. Endocr Rev 2021; 42:815-838. [PMID: 33743013 PMCID: PMC8599201 DOI: 10.1210/endrev/bnab008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 12/15/2022]
Abstract
Plasma triglyceride-rich lipoproteins (TRL), particularly atherogenic remnant lipoproteins, contribute to atherosclerotic cardiovascular disease. Hypertriglyceridemia may arise in part from hypersecretion of TRLs by the liver and intestine. Here we focus on the complex network of hormonal, nutritional, and neuronal interorgan communication that regulates secretion of TRLs and provide our perspective on the relative importance of these factors. Hormones and peptides originating from the pancreas (insulin, glucagon), gut [glucagon-like peptide 1 (GLP-1) and 2 (GLP-2), ghrelin, cholecystokinin (CCK), peptide YY], adipose tissue (leptin, adiponectin) and brain (GLP-1) modulate TRL secretion by receptor-mediated responses and indirectly via neural networks. In addition, the gut microbiome and bile acids influence lipoprotein secretion in humans and animal models. Several nutritional factors modulate hepatic lipoprotein secretion through effects on the central nervous system. Vagal afferent signaling from the gut to the brain and efferent signals from the brain to the liver and gut are modulated by hormonal and nutritional factors to influence TRL secretion. Some of these factors have been extensively studied and shown to have robust regulatory effects whereas others are "emerging" regulators, whose significance remains to be determined. The quantitative importance of these factors relative to one another and relative to the key regulatory role of lipid availability remains largely unknown. Our understanding of the complex interorgan regulation of TRL secretion is rapidly evolving to appreciate the extensive hormonal, nutritional, and neural signals emanating not only from gut and liver but also from the brain, pancreas, and adipose tissue.
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Affiliation(s)
- Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Avital Nahmias
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lili Tian
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary Franklin Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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12
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Morrow NM, Hanson AA, Mulvihill EE. Distinct Identity of GLP-1R, GLP-2R, and GIPR Expressing Cells and Signaling Circuits Within the Gastrointestinal Tract. Front Cell Dev Biol 2021; 9:703966. [PMID: 34660576 PMCID: PMC8511495 DOI: 10.3389/fcell.2021.703966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 08/16/2021] [Indexed: 12/17/2022] Open
Abstract
Enteroendocrine cells directly integrate signals of nutrient content within the gut lumen with distant hormonal responses and nutrient disposal via the production and secretion of peptides, including glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1) and glucagon-like peptide 2 (GLP-2). Given their direct and indirect control of post-prandial nutrient uptake and demonstrated translational relevance for the treatment of type 2 diabetes, malabsorption and cardiometabolic disease, there is significant interest in the locally engaged circuits mediating these metabolic effects. Although several specific populations of cells in the intestine have been identified to express endocrine receptors, including intraepithelial lymphocytes (IELs) and αβ and γδ T-cells (Glp1r+) and smooth muscle cells (Glp2r+), the definitive cellular localization and co-expression, particularly in regards to the Gipr remain elusive. Here we review the current state of the literature and evaluate the identity of Glp1r, Glp2r, and Gipr expressing cells within preclinical and clinical models. Further elaboration of our understanding of the initiating G-protein coupled receptor (GPCR) circuits engaged locally within the intestine and how they become altered with high-fat diet feeding can offer insight into the dysregulation observed in obesity and diabetes.
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Affiliation(s)
- Nadya M Morrow
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Antonio A Hanson
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Erin E Mulvihill
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Montreal Diabetes Research Center CRCHUM-Pavillion R, Montreal, QC, Canada.,Centre for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON, Canada
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13
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Jacome-Sosa M, Hu Q, Manrique-Acevedo CM, Phair RD, Parks EJ. Human intestinal lipid storage through sequential meals reveals faster dinner appearance is associated with hyperlipidemia. JCI Insight 2021; 6:e148378. [PMID: 34369385 PMCID: PMC8489663 DOI: 10.1172/jci.insight.148378] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/30/2021] [Indexed: 12/14/2022] Open
Abstract
Background It is increasingly recognized that intestinal cells can store lipids after a meal, yet the effect of this phenomenon on lipid absorption patterns in insulin resistance remains unknown. Methods The kinetics of meal fat appearance were measured in insulin-sensitive (IS, n = 8) and insulin-resistant (IR, n = 8) subjects after sequential, isotopically labeled lunch and dinner meals. Plasma dynamics on triacylglycerol-rich (TAG-rich) lipoproteins and plasma hormones were analyzed using a nonlinear, non–steady state kinetic model. Results At the onset of dinner, IS subjects showed an abrupt plasma appearance of lunch lipid consistent with the “second-meal effect,” followed by slower appearance of dinner fat in plasma, resulting in reduced accumulation of dinner TAG of 48% compared with lunch. By contrast, IR subjects exhibited faster meal TAG appearance rates after both lunch and dinner. This effect of lower enterocyte storage between meals was associated with greater nocturnal and next-morning hyperlipidemia. The biochemical data and the kinetic analysis of second-meal effect dynamics are consistent with rapid secretion of stored TAG bypassing lipolysis and resynthesis. In addition, the data are consistent with a role for the diurnal pattern of plasma leptin in regulating the processing of dietary lipid. Conclusion These data support the concept that intestinal lipid storage may be physiologically beneficial in IS subjects. Trial registration ClinicalTrials.gov NCT02020343. Funding This study was supported by a grant from the American Diabetes Association (grant 1-13-TS-12).
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Affiliation(s)
| | - Qiong Hu
- Department of Nutrition and Exercise Physiology and
| | | | - Robert D Phair
- Integrative Bioinformatics, Inc., Mountain View, California, USA
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology and.,Division of Gastroenterology and Hepatology, School of Medicine, University of Missouri, Columbia, Missouri, USA
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14
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Jang HR, Lee HY. Mechanisms linking gut microbial metabolites to insulin resistance. World J Diabetes 2021; 12:730-744. [PMID: 34168724 PMCID: PMC8192250 DOI: 10.4239/wjd.v12.i6.730] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/23/2021] [Accepted: 05/20/2021] [Indexed: 02/06/2023] Open
Abstract
Insulin resistance is the rate-limiting step in the development of metabolic diseases, including type 2 diabetes. The gut microbiota has been implicated in host energy metabolism and metabolic diseases and is recognized as a quantitatively important organelle in host metabolism, as the human gut harbors 10 trillion bacterial cells. Gut microbiota break down various nutrients and produce metabolites that play fundamental roles in host metabolism and aid in the identification of possible therapeutic targets for metabolic diseases. Therefore, understanding the various effects of bacterial metabolites in the development of insulin resistance is critical. Here, we review the mechanisms linking gut microbial metabolites to insulin resistance in various insulin-responsive tissues.
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Affiliation(s)
- Hye Rim Jang
- Laboratory of Mitochondrial and Metabolic Diseases, Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, South Korea
| | - Hui-Young Lee
- Laboratory of Mitochondrial and Metabolic Diseases, Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, South Korea
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 21999, South Korea
- Division of Molecular Medicine, Department of Medicine, Gachon University College of Medicine, Incheon 21936, South Korea
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15
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Carvalho LSF, Benseñor IM, Nogueira ACC, Duncan BB, Schmidt MI, Blaha MJ, Toth PP, Jones SR, Santos RD, Lotufo PA, Sposito AC. Increased particle size of triacylglycerol-enriched remnant lipoproteins, but not their plasma concentration or lipid content, augments risk prediction of incident type 2 diabetes. Diabetologia 2021; 64:385-396. [PMID: 33159534 DOI: 10.1007/s00125-020-05322-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes prevention requires the accurate identification of those at high risk. Beyond the association of fasting serum triacylglycerols with diabetes, triacylglycerol-enriched remnant lipoproteins (TRLs) more accurately reflect pathophysiological changes that underlie progression to diabetes, such as hepatic insulin resistance, pancreatic steatosis and systemic inflammation. We hypothesised that TRL-related factors could improve risk prediction for incident diabetes. METHODS We included individuals from the Brazilian Longitudinal Study of Adult Health cohort. We trained a logistic regression model for the risk of incident diabetes in 80% of the cohort using tenfold cross-validation, and tested the model in the remaining 20% of the cohort (test set). Variables included medical history and traits of the metabolic syndrome, followed by TRL-related measurements (plasma concentration, TRL particle diameter, cholesterol and triacylglycerol content). TRL features were measured using NMR spectroscopy. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). RESULTS Among 4463 at-risk individuals, there were 366 new cases of diabetes after a mean (±SD) of 3.7 (±0.63) years of follow-up. We derived an 18-variable model with a global AUROC of 0.846 (95% CI: 0.829, 0.869). Overall TRL-related markers were not associated with diabetes. However, TRL particle diameter increased the AUROC, particularly in individuals with HbA1c <39 mmol/mol (5.7%) (hold-out test set [n = 659]; training-validation set [n = 2638]), but not in individuals with baseline HbA1c 39-46 mmol/mol (5.7-6.4%) (hold-out test set [n = 233]; training-validation set [n = 933]). In the subgroup with baseline HbA1c <39 mmol/mol (5.7%), AUROC in the test set increased from 0.717 (95% CI 0.603, 0.818) to 0.794 (95% CI 0.731, 0.862), and AUPRC in the test set rose from 0.582 to 0.701 when using the baseline model and the baseline model plus TRL particle diameter, respectively. TRL particle diameter was highly correlated with obesity, insulin resistance and inflammation in those with impaired fasting glucose at baseline, but less so in those with HbA1c <39 mmol/mol (5.7%). CONCLUSIONS/INTERPRETATION TRL particle diameter improves the prediction of diabetes, but only in individuals with HbA1c <39 mmol/mol (5.7%) at baseline. These data support TRL particle diameter as a risk factor that is changed early in the course of the pathophysiological processes that lead to the development of type 2 diabetes, even before glucose abnormalities are established. Graphical abstract.
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Affiliation(s)
- Luiz Sérgio F Carvalho
- Data Lab, Clarity Healthcare Intelligence, Jundiaí, SP, Brazil.
- Cardiology Division, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, SP, Brazil.
- Laboratory of Data for Quality of Care and Outcomes Research, Institute for Strategic Management in Healthcare DF (IGESDF), Brasília, DF, Brazil.
| | - Isabela M Benseñor
- Center for Clinical and Epidemiological Research, University Hospital, University of São Paulo, São Paulo, SP, Brazil
| | - Ana C C Nogueira
- Laboratory of Data for Quality of Care and Outcomes Research, Institute for Strategic Management in Healthcare DF (IGESDF), Brasília, DF, Brazil
| | - Bruce B Duncan
- Postgraduate Studies Program in Epidemiology, School of Medicine and Hospital de Clínicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Maria I Schmidt
- Postgraduate Studies Program in Epidemiology, School of Medicine and Hospital de Clínicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Michael J Blaha
- The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA
| | - Peter P Toth
- The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA
- Preventive Cardiology, CGH Medical Center, Sterling, IL, USA
| | - Steven R Jones
- The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA
| | - Raul D Santos
- Center for Clinical and Epidemiological Research, University Hospital, University of São Paulo, São Paulo, SP, Brazil
- Lipid Clinic Heart Institute (InCor), University of São Paulo, Medical School Hospital, São Paulo, SP, Brazil
| | - Paulo A Lotufo
- Center for Clinical and Epidemiological Research, University Hospital, University of São Paulo, São Paulo, SP, Brazil
| | - Andrei C Sposito
- Cardiology Division, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, SP, Brazil
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16
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Wheeler MJ, Green DJ, Cerin E, Ellis KA, Heinonen I, Lewis J, Naylor LH, Cohen N, Larsen R, Dempsey PC, Kingwell BA, Owen N, Dunstan DW. Combined effects of continuous exercise and intermittent active interruptions to prolonged sitting on postprandial glucose, insulin, and triglycerides in adults with obesity: a randomized crossover trial. Int J Behav Nutr Phys Act 2020; 17:152. [PMID: 33308235 PMCID: PMC7734727 DOI: 10.1186/s12966-020-01057-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 11/11/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Postprandial glucose, insulin, and triglyceride metabolism is impaired by prolonged sitting, but enhanced by exercise. The aim of this study was to assess the effects of a continuous exercise bout with and without intermittent active interruptions to prolonged sitting on postprandial glucose, insulin, and triglycerides. METHODS Sedentary adults who were overweight to obese (n = 67; mean age 67 yr SD ± 7; BMI 31.2 kg∙m- 2 SD ± 4.1), completed three conditions: SIT: uninterrupted sitting (8-h, control); EX+SIT: sitting (1-h), moderate-intensity walking (30-min), uninterrupted sitting (6.5-h); EX+BR: sitting (1-h), moderate-intensity walking (30- min), sitting interrupted every 30-min with 3-min of light-intensity walking (6.5 h). Participants consumed standardized breakfast and lunch meals and blood was sampled at 13 time-points. RESULTS When compared to SIT, EX+SIT increased total area under the curve (tAUC) for glucose by 2% [0.1-4.1%] and EX+BR by 3% [0.6-4.7%] (all p < 0.05). Compared to SIT, EX+SIT reduced insulin and insulin:glucose ratio tAUC by 18% [11-22%] and 21% [8-33%], respectively; and EX+BR reduced values by 25% [19-31%] and 28% [15-38%], respectively (all p < 0.001 vs SIT, all p < 0.05 EX+SIT-vs-EX+BR). Compared to SIT, EX+BR reduced triglyceride tAUC by 6% [1-10%] (p = 0.01 vs SIT), and compared to EX+SIT, EX+BR reduced this value by 5% [0.1-8.8%] (p = 0.047 vs EX+SIT). The magnitude of reduction in insulin tAUC from SIT-to-EX+BR was greater in those with increased basal insulin resistance. No reduction in triglyceride tAUC from SIT-to-EX+BR was apparent in those with high fasting triglycerides. CONCLUSIONS Additional reductions in postprandial insulin-glucose dynamics and triglycerides may be achieved by combining exercise with breaks in sitting. Relative to uninterrupted sitting, this strategy may reduce postprandial insulin more in those with high basal insulin resistance, but those with high fasting triglycerides may be resistant to such intervention-induced reductions in triglycerides. TRIAL REGISTRATION Australia New Zealand Clinical Trials Registry ( ACTRN12614000737639 ).
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Affiliation(s)
- Michael J Wheeler
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia.
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia.
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia.
| | - Daniel J Green
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia
| | - Ester Cerin
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
- School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Kathryn A Ellis
- Department of Psychiatry, University of Melbourne, Parkville, VIC, Australia
| | - Ilkka Heinonen
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia
- Turku PET Centre, University of Turku, Turku, Finland
- Rydberg Laboratory of Applied Sciences, ETN, Halmstad University, Halmstad, Sweden
| | - Jaye Lewis
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia
| | - Louise H Naylor
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia
| | - Neale Cohen
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
| | - Robyn Larsen
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
| | - Paddy C Dempsey
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
- MRC Epidemiology Unit, Institute of Metabolic Science, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Diabetes Research Centre, University of Leicester, Leicester General Hospital, Leicester, UK
| | - Bronwyn A Kingwell
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
| | - Neville Owen
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
- Centre for Urban Transitions, Swinburne University of Technology, Hawthorn, Australia
| | - David W Dunstan
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia
- Baker Heart and Diabetes Institute, 99 Commercial Rd, Melbourne, Victoria, 3004, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
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17
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Straub RH. The memory of the fatty acid system. Prog Lipid Res 2020; 79:101049. [PMID: 32589906 DOI: 10.1016/j.plipres.2020.101049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 12/15/2022]
Abstract
Mental memory system has sensory memory, short-term memory, working memory, and long-term memory. Working memory "keeps things in mind in parallel" when performing complex tasks. Similar aspects can be found for immunological memory. However, there exists another one, the memory of the fatty acid system. This article shows sensory memory of the fatty acid system, which is the perception apparatus of small intestine enterocytes (CD36, SR-B1, FATP4, FABP1, FABP2) and hepatocytes. In these cells, the fatty acid short-term memory is located, consisting of a cytoplasmic lipid droplet cycle. Similar like a working memory in the brain, the short-term memory of enterocytes and hepatocytes use parallel processing and recourse to long-term fatty acid memory. The fatty acid long-term memory is far away from these primary points of uptake. It is located in the adipocyte and in cellular membranes. The process of building a fatty acid memory is described with constructs like sensing environmental material, encoding, consolidation, long-term storage, retrieval, re-encoding, re-consolidation, and renewed long-term storage. The article illustrates the dynamics of building a fatty acid memory, the information content of fatty acids including the code, the roles of fatty acids in the body, and a new understanding of the expression "you are what you eat". The memory of the fatty acid system, plays a decisive role in integrating environmental signals over time (diet and microbiome).
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Affiliation(s)
- Rainer H Straub
- Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Department of Internal Medicine, University Hospital, Regensburg, Germany.
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18
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Stemmer K, Finan B, DiMarchi RD, Tschöp MH, Müller TD. Insights into incretin-based therapies for treatment of diabetic dyslipidemia. Adv Drug Deliv Rev 2020; 159:34-53. [PMID: 32485206 DOI: 10.1016/j.addr.2020.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/09/2020] [Accepted: 05/23/2020] [Indexed: 02/07/2023]
Abstract
Derangements in triglyceride and cholesterol metabolism (dyslipidemia) are major risk factors for the development of cardiovascular diseases in obese and type-2 diabetic (T2D) patients. An emerging class of glucagon-like peptide-1 (GLP-1) analogues and next generation peptide dual-agonists such as GLP-1/glucagon or GLP-1/GIP could provide effective therapeutic options for T2D patients. In addition to their role in glucose and energy homeostasis, GLP-1, GIP and glucagon serve as regulators of lipid metabolism. This review summarizes the current knowledge in GLP-1, glucagon and GIP effects on lipid and lipoprotein metabolism and frames the emerging therapeutic benefits of GLP-1 analogs and GLP-1-based multiagonists as add-on treatment options for diabetes associated dyslipidemia.
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19
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Farr S, Stankovic B, Hoffman S, Masoudpoor H, Baker C, Taher J, Dean AE, Anakk S, Adeli K. Bile acid treatment and FXR agonism lower postprandial lipemia in mice. Am J Physiol Gastrointest Liver Physiol 2020; 318:G682-G693. [PMID: 32003602 DOI: 10.1152/ajpgi.00386.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Postprandial dyslipidemia is a common feature of insulin-resistant states and contributes to increased cardiovascular disease risk. Recently, bile acids have been recognized beyond their emulsification properties as important signaling molecules that promote energy expenditure, improve insulin sensitivity, and lower fasting lipemia. Although bile acid receptors have become novel pharmaceutical targets, their effects on postprandial lipid metabolism remain unclear. Here, we investigated the potential role of bile acids in regulation of postprandial chylomicron production and triglyceride excursion. Healthy C57BL/6 mice were given an intraduodenal infusion of taurocholic acid (TA) under fat-loaded conditions, and circulating lipids were measured. Targeting of bile acid receptors was achieved with GW4064, a synthetic agonist to the farnesoid X receptor (FXR), and deoxycholic acid (DCA), an activator of the Takeda G-protein-coupled receptor 5. TA, GW4064, and DCA treatments all lowered postprandial lipemia. FXR agonism also reduced intestinal triglyceride content and activity of microsomal triglyceride transfer protein, involved in chylomicron assembly. Importantly, TA (but not DCA) effects were largely lost in FXR knockout mice. These bile acid effects are reminiscent of the antidiabetic hormone glucagon-like peptide-1 (GLP-1). Although the GLP-1 receptor agonist exendin-4 retained its ability to acutely lower postprandial lipemia during bile acid sequestration and FXR deficiency, it did raise hepatic expression of the rate-limiting enzyme for bile acid synthesis. Bile acid signaling may be an important mechanism of controlling dietary lipid absorption, and bile acid receptors may constitute novel targets for the treatment of postprandial dyslipidemia.NEW & NOTEWORTHY We present new data suggesting potentially important roles for bile acids in regulation of postprandial lipid metabolism. Specific bile acid species, particularly secondary bile acids, were found to markedly inhibit absorption of dietary lipid and reduce postprandial triglyceride excursion. These effects appear to be mediated via bile acid receptors, farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5). Importantly, bile acid signaling may trigger glucagon-like peptide-1 (GLP-1) secretion, which may in turn mediate the marked inhibitory effects on dietary fat absorption.
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Affiliation(s)
- Sarah Farr
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.,Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Bogdan Stankovic
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.,Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon Hoffman
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.,Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hassan Masoudpoor
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chris Baker
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jennifer Taher
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.,Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Angela E Dean
- Molecular and Cellular Biology, University of Illinois-Urbana-Champaign, Urbana, Illinois
| | | | - Khosrow Adeli
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada.,Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
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20
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Bittel AJ, Bittel DC, Mittendorfer B, Patterson BW, Okunade AL, Yoshino J, Porter LC, Abumrad NA, Reeds DN, Cade WT. A single bout of resistance exercise improves postprandial lipid metabolism in overweight/obese men with prediabetes. Diabetologia 2020; 63:611-623. [PMID: 31873788 PMCID: PMC7002271 DOI: 10.1007/s00125-019-05070-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Prediabetes is associated with postprandial hypertriacylglycerolaemia. Resistance exercise acutely lowers postprandial plasma triacylglycerol (TG); however, the changes in lipid metabolism that mediate this reduction are poorly understood. The aim of this study was to identify the constitutive metabolic mechanisms underlying the changes in postprandial lipid metabolism after resistance exercise in obese men with prediabetes. METHODS We evaluated the effect of a single bout of whole-body resistance exercise (seven exercises, three sets, 10-12 repetitions at 80% of one-repetition maximum) on postprandial lipid metabolism in ten middle-aged (50 ± 9 years), overweight/obese (BMI: 33 ± 3 kg/m2), sedentary men with prediabetes (HbA1c >38 but <48 mmol/mol [>5.7% but <6.5%]), or fasting plasma glucose >5.6 mmol/l but <7.0 mmol/l or 2 h OGTT glucose >7.8 mmol/l but <11.1 mmol/l). We used a randomised, crossover design with a triple-tracer mixed meal test (ingested [(13C4)3]tripalmitin, i.v. [U-13C16]palmitate and [2H5]glycerol) to evaluate chylomicron-TG and total triacylglycerol-rich lipoprotein (TRL)-TG kinetics. We used adipose tissue and skeletal muscle biopsies to evaluate the expression of genes regulating lipolysis and lipid oxidation, skeletal muscle respirometry to evaluate oxidative capacity, and indirect calorimetry to assess whole-body lipid oxidation. RESULTS The single bout of resistance exercise reduced the lipaemic response to a mixed meal in obese men with prediabetes without changing chylomicron-TG or TRL-TG fractional clearance rates. However, resistance exercise reduced endogenous and meal-derived fatty acid incorporation into chylomicron-TG and TRL-TG. Resistance exercise also increased whole-body lipid oxidation, skeletal muscle mitochondrial respiration, oxidative gene expression in skeletal muscle, and the expression of key lipolysis genes in adipose tissue. CONCLUSIONS/INTERPRETATION A single bout of resistance exercise improves postprandial lipid metabolism in obese men with prediabetes, which may mitigate the risk for cardiovascular disease and type 2 diabetes.
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Affiliation(s)
- Adam J Bittel
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA.
| | - Daniel C Bittel
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Bruce W Patterson
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Adewole L Okunade
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Jun Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Lane C Porter
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Nada A Abumrad
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - Dominic N Reeds
- Center for Human Nutrition, Washington University School of Medicine, St Louis, MO, USA
| | - W Todd Cade
- Program in Physical Therapy, Washington University, St Louis, Campus Box 8502, 4444 Forest Park Ave., St Louis, MO, 63110, USA
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Stahel P, Xiao C, Nahmias A, Lewis GF. Role of the Gut in Diabetic Dyslipidemia. Front Endocrinol (Lausanne) 2020; 11:116. [PMID: 32231641 PMCID: PMC7083132 DOI: 10.3389/fendo.2020.00116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). In insulin resistant states such as the metabolic syndrome, overproduction and impaired clearance of liver-derived very-low-density lipoproteins and gut-derived chylomicrons (CMs) contribute to hypertriglyceridemia and elevated atherogenic remnant lipoproteins. Although ingested fat is the major stimulus of CM secretion, intestinal lipid handling and ultimately CM secretory rate is determined by numerous additional regulatory inputs including nutrients, hormones and neural signals that fine tune CM secretion during fasted and fed states. Insulin resistance and T2D represent perturbed metabolic states in which intestinal sensitivity to key regulatory hormones such as insulin, leptin and glucagon-like peptide-1 (GLP-1) may be altered, contributing to increased CM secretion. In this review, we describe the evidence from human and animal models demonstrating increased CM secretion in insulin resistance and T2D and discuss the molecular mechanisms underlying these effects. Several novel compounds are in various stages of preclinical and clinical investigation to modulate intestinal CM synthesis and secretion. Their efficacy, safety and therapeutic utility are discussed. Similarly, the effects of currently approved lipid modulating therapies such as statins, ezetimibe, fibrates, and PCSK9 inhibitors on intestinal CM production are discussed. The intricacies of intestinal CM production are an active area of research that may yield novel therapies to prevent atherosclerotic CVD in insulin resistance and T2D.
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Drouin-Chartier JP, Tremblay AJ, Lemelin V, Lamarche B, Couture P. Differential associations between plasma concentrations of insulin and glucose and intestinal expression of key genes involved in chylomicron metabolism. Am J Physiol Gastrointest Liver Physiol 2018; 315:G177-G184. [PMID: 29698057 DOI: 10.1152/ajpgi.00108.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mechanisms underlying the oversecretion of apolipoprotein (apo)B-48-containing triglyceride-rich lipoproteins (TRL) in insulin-resistance (IR) states in humans remain to be fully understood. The objective of this study was to evaluate the association between the plasma levels of insulin and glucose and the intestinal expression of key genes involved in chylomicron metabolism in a large sample of nondiabetic men displaying various degrees of IR. Duodenal biopsies were obtained by gastroduodenoscopy in 127 men free of intestinal disease. Gene expression was measured using quantitative PCR in duodenal samples. Plasma insulin and glucose concentrations were measured in the fasting state. Postprandial TRL apoB-48 kinetics were measured using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h in a subgroup of 75 subjects maintained in a constant fed state. Plasma insulin levels were negatively associated with intestinal expression of ACS1 (standard β = -0.20, P = 0.007), DGAT1 (β = -0.18, P = 0.001), DGAT2 (β = -0.20, P = 0.02), and MTP (β = -0.27, P = 0.0005), whereas glucose levels were positively associated with MTP expression (β = 0.15, P = 0.04) independent of age, BMI, waist circumference, dietary intake, and duodenal expression of SREBP1c. Insulin levels, but not glucose concentrations, were positively correlated with postprandial TRL apoB-48 production rate ( r = 0.24, P = 0.04) and pool size ( r = 0.27, P = 0.03). In conclusion, plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism. These results suggest that alterations in intestinal lipoprotein metabolism associated with IR may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency. NEW & NOTEWORTHY We demonstrate that plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism in men. For instance, intestinal expression of MTP is negatively associated with plasma insulin concentrations and positively associated with plasma glucose concentrations. Alterations in intestinal lipoprotein metabolism associated with insulin resistance may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency.
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Affiliation(s)
| | - André J Tremblay
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada
| | - Valéry Lemelin
- Department of Gastroenterology, Centre hospitalier universitaire de Québec-Laval University , Quebec City, Quebec , Canada
| | - Benoît Lamarche
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods, Laval University , Quebec City, Quebec , Canada.,Lipid Research Centre, Centre hospitalier universitaire de Québec-Laval University , Quebec City, Quebec , Canada
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23
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Chen XM, Zhang WQ, Tian Y, Wang LF, Chen CC, Qiu CM. Liraglutide suppresses non-esterified free fatty acids and soluble vascular cell adhesion molecule-1 compared with metformin in patients with recent-onset type 2 diabetes. Cardiovasc Diabetol 2018; 17:53. [PMID: 29636047 PMCID: PMC5891985 DOI: 10.1186/s12933-018-0701-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/05/2018] [Indexed: 01/28/2023] Open
Abstract
Background It has been suggested that liraglutide could have an impact on glucose and lipid metabolism disorder and adhesion molecule activation, which may play important roles in the vascular damage of diabetes. In this study, we examined the effects of liraglutide versus metformin on non-esterified free fatty acids, beta-cell insulin secretion, and adhesion molecule levels in patients with recent-onset type 2 diabetes mellitus. Methods In this study, 60 patients newly diagnosed with type 2 diabetes mellitus (mean age 33.97 ± 5.67 years) were randomly assigned to receive once-daily subcutaneous liraglutide or oral metformin. Before the study and after the 8-week treatment period, a 75 g oral glucose tolerance test was performed. Plasma glucose, lipids and lipoprotein, plasma insulin, glycaemic and insulin responses, non-esterified free fatty acids (NEFA), and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were evaluated. Results After 8 weeks, 120 min of NEFA (155 ± 125 vs 99 ± 73 µmol/L, P = 0.026) and the levels of sVCAM-1 (465 ± 136 vs 382 ± 131 ng/ml, P = 0.013) significantly decreased, while the early phase insulin secretion index (24.94 [7.78, 38.89] vs. 31.13 [17.67, 59.09], P = 0.031), fasting plasma insulin (104 [51, 123] vs 113 [54, 171] mIU/L, P = 0.015), 60 min plasma insulin (326 [165, 441] vs 471 [334, 717] mIU/L, P = 0.005), 120 min plasma insulin (401 [193, 560] vs 500 [367, 960] mIU/L, P = 0.047), and insulin area under the curve (AUCins) (648 [321, 742] vs 738 [451, 1118] mIU/L, P = 0.005) remarkably increased for patients in the liraglutide treatment group. The levels of sVCAM-1 dramatically decreased after 8 weeks of liraglutide treatment (503 ± 182 vs 382 ± 131 ng/ml, P = 0.046) compared to that of the metformin treatment group. At the same time, the differences before and after liraglutide treatment in 120 min of NEFA (− 32 [− 96, − 5] vs 5 [− 35, 38] µmol/L, P = 0.033) and AUCins (738 [451, 1118] vs 594 [357, 1216] mIU/L, P = 0.014) were remarkably enhanced compared to that of the metformin therapy. Nevertheless, there were no significant differences in fasting NEFA after liraglutide or metformin treatment. The reduction of 120 min NEFA (ΔNEFA) was positively correlated with the decrease of sVCAM-1 (ΔsVCAM-1) after 8 weeks of liraglutide treatment (r = 0.523, P = 0.003). Conclusions Our results demonstrate that liraglutide administration is more effective than metformin in reducing 120 min NEFA and suppressing sVCAM-1 levels for recent-onset type 2 diabetes mellitus. We suggest that this outcome may be because liraglutide is associated with potentiating insulin secretion capacity, inhibiting vascular inflammatory cytokines, and antagonizing atherosclerosis. Electronic supplementary material The online version of this article (10.1186/s12933-018-0701-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiao-Min Chen
- Department of Endocrinology and Metabolism, Zhongshan Hospital Xiamen University, 201-209 Hubin South Road, Xiamen, 361004, People's Republic of China.
| | - Wen-Qiang Zhang
- Department of Endocrinology and Metabolism, Zhongshan Hospital Xiamen University, 201-209 Hubin South Road, Xiamen, 361004, People's Republic of China
| | - Yuan Tian
- Department of Endocrinology and Metabolism, Zhongshan Hospital Xiamen University, 201-209 Hubin South Road, Xiamen, 361004, People's Republic of China
| | - Li-Fen Wang
- Guangzhou Medicine University Second Affiliated Hospital, 250-296 Changgang East Road, Guangzhou, 510260, People's Republic of China
| | - Chan-Chan Chen
- Department of Endocrinology and Metabolism, Zhongshan Hospital Xiamen University, 201-209 Hubin South Road, Xiamen, 361004, People's Republic of China
| | - Chuan-Mei Qiu
- Department of Endocrinology and Metabolism, Zhongshan Hospital Xiamen University, 201-209 Hubin South Road, Xiamen, 361004, People's Republic of China
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24
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Mulvihill EE. Regulation of intestinal lipid and lipoprotein metabolism by the proglucagon-derived peptides glucagon like peptide 1 and glucagon like peptide 2. Curr Opin Lipidol 2018; 29:95-103. [PMID: 29432213 PMCID: PMC5882252 DOI: 10.1097/mol.0000000000000495] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW The intestine is highly efficient at absorbing and packaging dietary lipids onto the structural protein apoB48 for distribution throughout the body. Here, we summarize recent advances into understanding the physiological and pharmacological actions of the proglucagon-derived peptides: glucagon like peptide 1 (GLP-1) and glucagon like peptide 2 (GLP-2) on intestinal lipoprotein secretion. RECENT FINDINGS Several recent studies have elucidated mechanisms underlying the paradoxical effects of GLP-1 and GLP-2 on intestinal production of triglyceride-rich lipoproteins (TRLs). Both gut-derived peptides are secreted on an equimolar basis in response to the same nutrient stimulus. Despite neither receptor demonstrating clear localization to enterocytes, a single injection of a GLP-1R agonist rapidly decreases delivery of intestinally packaged fatty acids into the plasma, while conversely GLP-2 receptor (GLP-2R) activation acutely increases TRL concentrations in plasma. SUMMARY The regulation of TRL secretion is dependent on the coordination of many processes: fatty acid availability uptake, assembly onto the apoB48 polypeptide backbone, secretion and reuptake, which the hormonal, neural, inflammatory and metabolic milieu can all strongly influence. Understanding of how GLP-1 and GLP-2 receptor agonists control TRL production has clinical importance given that GLP1R agonists were recently demonstrated not only to provide glycemic control but also to prevent major adverse cardiovascular events in patients with T2DM and the success of GLP-2R agonists in treating short bowel disease.
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Affiliation(s)
- Erin E Mulvihill
- University of Ottawa Heart Institute, University of Ottawa, Department of Biochemistry, Microbiology and Immunology, Ottawa, Ontario, Canada
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25
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Xiao C, Stahel P, Carreiro AL, Buhman KK, Lewis GF. Recent Advances in Triacylglycerol Mobilization by the Gut. Trends Endocrinol Metab 2018; 29:151-163. [PMID: 29306629 DOI: 10.1016/j.tem.2017.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
Dietary lipid absorption and lipoprotein secretion by the gut are important in maintaining whole-body energy homeostasis and have significant implications for health and disease. The processing of dietary lipids, including storage within and subsequent mobilization and transport from enterocyte cytoplasmic lipid droplets or other intestinal lipid storage pools (including the secretary pathway, lamina propria and lymphatics) and secretion of chylomicrons, involves coordinated steps that are subject to various controls. This review summarizes recent advances in our understanding of the mechanisms that underlie lipid storage and mobilization by small intestinal enterocytes and the intestinal lymphatic vasculature. Therapeutic targeting of lipid processing by the gut may provide opportunities for the treatment and prevention of dyslipidemia, and for improving health status.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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26
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Higgins V, Adeli K. Postprandial Dyslipidemia: Pathophysiology and Cardiovascular Disease Risk Assessment. EJIFCC 2017; 28:168-184. [PMID: 29075168 PMCID: PMC5655632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the fed state predominates over the course of a day, the fasting lipid profile has traditionally been used to assess cardiovascular disease (CVD) risk. The nonfasting lipid profile may be more reflective of the daily circulating plasma lipids and simplifies lipid monitoring for patients, laboratories, and clinicians. Nonfasting triglyceride levels are also independently associated with cardiovascular events, leading to several clinical guidelines (e.g. in Denmark, the UK, Europe, and Canada) now recommending nonfasting lipid testing in the primary prevention setting. Obese and insulin resistant states are associated with intestinal chylomicron overproduction and subsequent remnant lipoprotein accumulation, leading to development of postprandial dyslipidemia in the fed state. Postprandial dyslipidemia is thought to be a major contributor of atherogenesis and shown to be an important CVD risk factor. As intestinal peptides (e.g. glucagon-like-peptide 1; GLP-1) have been shown to regulate chylomicron output, alterations in these signaling pathways in insulin resistant states may play a role in the development and/or progression of postprandial dyslipidemia. Although several advances have been made in understanding postprandial dyslipidemia in insulin resistance and its association with CVD, several limitations remain. Although nonfasting lipid measurements (i.e. random blood sampling) are now recommended in some countries, a more functional assessment of postprandial lipemia involves ingestion of a high-fat meal with subsequent blood collection over a specified time period (i.e. oral fat tolerance test). However, oral fat tolerance test methodology remains largely unstandardized and reference values to interpret postprandial values remain to be accurately established. Development of standardized methodologies and biomarker profiles for assessment of postprandial dyslipidemia in clinical practice will enable early and accurate identification of those at risk for CVD.
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Affiliation(s)
- Victoria Higgins
- CALIPER Program, Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada, Department of Laboratory Medicine & Pathobiology, University of Toronto, Ontario, Canada
| | - Khosrow Adeli
- CALIPER Program, Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada, Department of Laboratory Medicine & Pathobiology, University of Toronto, Ontario, Canada,Clinical Biochemistry, DPLM The Hospital for Sick Children 555 University Avenue Toronto, ON, M5G 1X8 Canada
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27
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Søndergaard E, Johansen RF, Jensen MD, Nielsen S. Postprandial VLDL-TG metabolism in type 2 diabetes. Metabolism 2017; 75:25-35. [PMID: 28964326 DOI: 10.1016/j.metabol.2017.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/26/2017] [Accepted: 07/05/2017] [Indexed: 01/22/2023]
Abstract
BACKGROUND Type 2 diabetes is associated with excess postprandial lipemia due to accumulation of chylomicrons and VLDL particles. This is a risk factor for development of cardiovascular disease. However, whether the excess lipemia is associated with an impaired suppression of VLDL-TG secretion and/or reduced clearance into adipose tissue is unknown. OBJECTIVE We measured the postprandial VLDL-TG secretion, clearance and adipose tissue storage to test the hypothesis that impaired postprandial suppression of VLDL-TG secretion, combined with impaired VLDL-TG storage in adipose tissue, is associated with excess postprandial lipemia. DESIGN We studied 11 men with type 2 diabetes and 10 weight-matched non-diabetic men using ex-vivo labeled VLDL-TG tracers during an oral high-fat mixed-meal tolerance test to measure postprandial VLDL-TG secretion, clearance and storage. In addition, adipose tissue biopsies were analyzed for LPL activity and cellular storage factors. RESULTS Men with type 2 diabetes had greater postprandial VLDL-TG concentration compared to non-diabetic men. However, postprandial VLDL-TG secretion rate was similar in the two groups with equal suppression of VLDL-TG secretion rate (≈50%) and clearance rate. In addition, postprandial VLDL-TG storage was similar in the two groups in both upper body and lower body subcutaneous adipose tissue. CONCLUSIONS Despite greater postprandial VLDL-TG concentration, men with type 2 diabetes have similar postprandial suppression of VLDL-TG secretion and a similar ability to store VLDL-TG in adipose tissue compared to non-diabetic men. This may indicate that abnormalities in postprandial VLDL-TG metabolism are a consequence of obesity/insulin resistance more than a result of type 2 diabetes per se.
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Affiliation(s)
- Esben Søndergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark; Danish Diabetes Academy, Odense University Hospital, Kløvervænget 10, Entrance 112, 3rd floor, 5000 Odense C, Denmark; Endocrine Research Unit, Mayo Clinic, 1216 2nd St SW, Rochester, MN 55902, USA.
| | - Rakel Fuglsang Johansen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Michael D Jensen
- Endocrine Research Unit, Mayo Clinic, 1216 2nd St SW, Rochester, MN 55902, USA
| | - Søren Nielsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark
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Xiao C, Dash S, Stahel P, Lewis GF. Effects of Intranasal Insulin on Triglyceride-Rich Lipoprotein Particle Production in Healthy Men. Arterioscler Thromb Vasc Biol 2017; 37:1776-1781. [DOI: 10.1161/atvbaha.117.309705] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023]
Affiliation(s)
- Changting Xiao
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Satya Dash
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Priska Stahel
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Gary F. Lewis
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
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29
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Jensen SR, Wheeler SE, Hvid H, Ahnfelt-Rønne J, Hansen BF, Nishimura E, Olsen GS, Brubaker PL. Elucidating the Biological Roles of Insulin and Its Receptor in Murine Intestinal Growth and Function. Endocrinology 2017; 158:2453-2469. [PMID: 28591779 DOI: 10.1210/en.2017-00195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/01/2017] [Indexed: 12/14/2022]
Abstract
The role of the intestinal insulin receptor (IR) is not well understood. We therefore explored the effect of insulin (300 nmol/kg per day for 12 days) on the intestine in sex-matched C57Bl/6J mice. The intestinal and metabolic profiles were also characterized in male and female intestinal-epithelial IR knockout (IE-irKO) mice compared with all genetic controls on a chow diet or Western diet (WD) for 4 to 12 weeks. Insulin treatment did not affect intestinal size, intestinal resistance, or metabolic genes, but it reduced proximal-colon crypt depth and acutely increased colonic serine/threonine-specific protein kinase B (AKT) activation. Feeding with a WD increased body weight and fasting insulin level and decreased oral glucose tolerance in C57Bl/6J and IE-irKO mice. However, although the overall responses of the IE-irKO mice were not different from those of Villin-Cre (Vil-Cre):IRfl/+ and IRfl/fl controls, profound differences were found for female control Vil-Cre mice, which demonstrated reduced food intake, body weight, jejunal glucose transport, oral glucose tolerance, and fasting insulin and cholesterol levels. Vil-Cre mice also had smaller intestines compared with those of IE-irKO and IRfl/fl mice and greater insulin-mediated activation of jejunal IR and AKT. In summary, gain- and loss-of-function studies, with and without caloric overload, indicate that insulin did not exert remarkable effects on intestinal metabolic or morphologic phenotype except for a small effect on the colon. However, the transgenic control Vil-Cre mice displayed a distinct phenotype compared with other control and knockout animals, emphasizing the importance of thoroughly characterizing genetically modified mouse models.
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Affiliation(s)
- Stina Rikke Jensen
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Metabolic Disease Research, Novo Nordisk A/S, DK-2760 Måløv, Denmark
| | - Sarah E Wheeler
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Henning Hvid
- Metabolic Disease Research, Novo Nordisk A/S, DK-2760 Måløv, Denmark
| | | | - Bo Falck Hansen
- Metabolic Disease Research, Novo Nordisk A/S, DK-2760 Måløv, Denmark
| | - Erica Nishimura
- Metabolic Disease Research, Novo Nordisk A/S, DK-2760 Måløv, Denmark
| | | | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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30
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Steenson S, Umpleby AM, Lovegrove JA, Jackson KG, Fielding BA. Role of the Enterocyte in Fructose-Induced Hypertriglyceridaemia. Nutrients 2017; 9:nu9040349. [PMID: 28368310 PMCID: PMC5409688 DOI: 10.3390/nu9040349] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/21/2017] [Accepted: 03/31/2017] [Indexed: 01/12/2023] Open
Abstract
Dietary fructose has been linked to an increased post-prandial triglyceride (TG) level; which is an established independent risk factor for cardiovascular disease. Although much research has focused on the effects of fructose consumption on liver-derived very-low density lipoprotein (VLDL); emerging evidence also suggests that fructose may raise post-prandial TG levels by affecting the metabolism of enterocytes of the small intestine. Enterocytes have become well recognised for their ability to transiently store lipids following a meal and to thus control post-prandial TG levels according to the rate of chylomicron (CM) lipoprotein synthesis and secretion. The influence of fructose consumption on several aspects of enterocyte lipid metabolism are discussed; including de novo lipogenesis; apolipoprotein B48 and CM-TG production; based on the findings of animal and human isotopic tracer studies. Methodological issues affecting the interpretation of fructose studies conducted to date are highlighted; including the accurate separation of CM and VLDL. Although the available evidence to date is limited; disruption of enterocyte lipid metabolism may make a meaningful contribution to the hypertriglyceridaemia often associated with fructose consumption.
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Affiliation(s)
- Simon Steenson
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - A Margot Umpleby
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
| | - Julie A Lovegrove
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - Kim G Jackson
- Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading RG6 6AP, UK.
| | - Barbara A Fielding
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7WG, UK.
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31
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Higgins V, Adeli K. Pediatric Metabolic Syndrome: Pathophysiology and Laboratory Assessment. EJIFCC 2017; 28:25-42. [PMID: 28439217 PMCID: PMC5387698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Pediatric overweight and obesity is an emerging public health priority as rates have rapidly increased worldwide. Obesity is often clustered with other metabolic abnormalities including hypertension, dyslipidemia, and insulin resistance, leading to increased risk of cardiovascular disease. This cluster of risk factors, termed the metabolic syndrome, has traditionally been reported in adults. However, with the increased prevalence of pediatric obesity, the metabolic syndrome is now evident in children and adolescents. This complex cluster of risk factors is the result of the pathological interplay between several organs including adipose tissue, muscle, liver, and intestine with a common antecedent - insulin resistance. The association of the metabolic syndrome with several systemic alterations that involve numerous organs and tissues adds to the complexity and challenge of diagnosing the metabolic syndrome and identifying useful clinical indicators of the disease. The complex physiology of growing and developing children and adolescents further adds to the difficulties in standardizing laboratory assessment, diagnosis, and prognosis for the diverse pediatric population. However, establishing a consensus definition is critical to identifying and managing children and adolescents at high risk of developing the metabolic syndrome. As a result, the examination of novel metabolic syndrome biomarkers which can detect these metabolic abnormalities early with high specificity and sensitivity in the pediatric population has been of interest. Understanding this complex cluster of risk factors in the pediatric population is critical to ensure that this is not the first generation where children have a shorter life expectancy than their parents. This review will discuss the pathophysiology, consensus definitions and laboratory assessment of pediatric metabolic syndrome as well as potential novel biomarkers.
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Affiliation(s)
- Victoria Higgins
- Clinical Biochemistry, Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Khosrow Adeli
- Clinical Biochemistry, Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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32
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Abstract
Excess and ectopic fat accumulation in obesity is a major risk factor for developing hyperlipidemia, type 2 diabetes and cardiovascular disease. The activation of brown and/or beige adipocytes is a promising target for the treatment of metabolic disorders as the combustion of excess energy by these thermogenic adipocytes may help losing weight and improving plasma parameters including triglyceride, cholesterol and glucose levels. The regulation of heat production by thermogenic adipose tissues is based on a complex crosstalk between the autonomous nervous system, intracellular and secreted factors. This multifaceted alignment regulates thermogenic demands to environmental circumstances in dependence on available energy resources. This review summarizes the current knowledge how thermogenic tissues can be targeted to combat the burden of diseases with a special focus on lipid metabolism and diseases related to lipoprotein metabolism.
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Affiliation(s)
- Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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Tran TTT, Postal BG, Demignot S, Ribeiro A, Osinski C, Pais de Barros JP, Blachnio-Zabielska A, Leturque A, Rousset M, Ferré P, Hajduch E, Carrière V. Short Term Palmitate Supply Impairs Intestinal Insulin Signaling via Ceramide Production. J Biol Chem 2016; 291:16328-38. [PMID: 27255710 DOI: 10.1074/jbc.m115.709626] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Indexed: 12/16/2022] Open
Abstract
The worldwide prevalence of metabolic diseases is increasing, and there are global recommendations to limit consumption of certain nutrients, especially saturated lipids. Insulin resistance, a common trait occurring in obesity and type 2 diabetes, is associated with intestinal lipoprotein overproduction. However, the mechanisms by which the intestine develops insulin resistance in response to lipid overload remain unknown. Here, we show that insulin inhibits triglyceride secretion and intestinal microsomal triglyceride transfer protein expression in vivo in healthy mice force-fed monounsaturated fatty acid-rich olive oil but not in mice force-fed saturated fatty acid-rich palm oil. Moreover, when mouse intestine and human Caco-2/TC7 enterocytes were treated with the saturated fatty acid, palmitic acid, the insulin-signaling pathway was impaired. We show that palmitic acid or palm oil increases ceramide production in intestinal cells and that treatment with a ceramide analogue partially reproduces the effects of palmitic acid on insulin signaling. In Caco-2/TC7 enterocytes, ceramide effects on insulin-dependent AKT phosphorylation are mediated by protein kinase C but not by protein phosphatase 2A. Finally, inhibiting de novo ceramide synthesis improves the response of palmitic acid-treated Caco-2/TC7 enterocytes to insulin. These results demonstrate that a palmitic acid-ceramide pathway accounts for impaired intestinal insulin sensitivity, which occurs within several hours following initial lipid exposure.
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Affiliation(s)
- Thi Thu Trang Tran
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Bárbara Graziela Postal
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Sylvie Demignot
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Agnès Ribeiro
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Céline Osinski
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | | | | | - Armelle Leturque
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Monique Rousset
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France
| | - Pascal Ferré
- INSERM UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06, Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot, Institute of Cardiometabolism and Nutrition (ICAN), Centre de Recherche des Cordeliers, F-75006 Paris, France
| | - Eric Hajduch
- INSERM UMRS 1138, Sorbonne Universités, UPMC Univ Paris 06, Sorbonne Paris Cité, Université Paris Descartes, Université Paris Diderot, Institute of Cardiometabolism and Nutrition (ICAN), Centre de Recherche des Cordeliers, F-75006 Paris, France
| | - Véronique Carrière
- From the Centre de Recherche des Cordeliers, INSERM, UPMC Univ Paris 06, Sorbonne Universités, Université Paris Descartes, Sorbonne Paris Cité, Ecole Pratique des Hautes Etudes (EPHE), Université Paris Sciences et Lettres, Université Paris Diderot, CNRS, Institute of Cardiometabolism and Nutrition, F-75006 Paris, France,
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Xiao C, Dash S, Morgantini C, Lewis GF. Intravenous Glucose Acutely Stimulates Intestinal Lipoprotein Secretion in Healthy Humans. Arterioscler Thromb Vasc Biol 2016; 36:1457-63. [PMID: 27150393 DOI: 10.1161/atvbaha.115.307044] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/20/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Increased production of intestinal triglyceride-rich lipoproteins (TRLs) contributes to dyslipidemia and increased risk of atherosclerotic cardiovascular disease in insulin resistance and type 2 diabetes. We have previously demonstrated that enteral glucose enhances lipid-stimulated intestinal lipoprotein particle secretion. Here, we assessed whether glucose delivered systemically by intravenous infusion also enhances intestinal lipoprotein particle secretion in humans. APPROACH AND RESULTS On 2 occasions, 4 to 6 weeks apart and in random order, 10 healthy men received a constant 15-hour intravenous infusion of either 20% glucose to induce hyperglycemia or normal saline as control. Production of TRL-apolipoprotein B48 (apoB48, primary outcomes) and apoB100 (secondary outcomes) was assessed during hourly liquid-mixed macronutrient formula ingestion with stable isotope enrichment and multicompartmental modeling, under pancreatic clamp conditions to limit perturbations in pancreatic hormones (insulin and glucagon) and growth hormone. Compared with saline infusion, glucose infusion induced both hyperglycemia and hyperinsulinemia, increased plasma triglyceride levels, and increased TRL-apoB48 concentration and production rate (P<0.05), without affecting TRL-apoB48 fractional catabolic rate. No significant effect of hyperglycemia on TRL-apoB100 concentration and kinetic parameters was observed. CONCLUSIONS Short-term intravenous infusion of glucose stimulates intestinal lipoprotein production. Hyperglycemia may contribute to intestinal lipoprotein overproduction in type 2 diabetes. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT02607839.
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Affiliation(s)
- Changting Xiao
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Satya Dash
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Cecilia Morgantini
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Gary F Lewis
- From the Division of Endocrinology and Metabolism, Department of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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Jacome-Sosa M, Parks EJ, Bruno RS, Tasali E, Lewis GF, Schneeman BO, Rains TM. Postprandial Metabolism of Macronutrients and Cardiometabolic Risk: Recent Developments, Emerging Concepts, and Future Directions. Adv Nutr 2016; 7:364-74. [PMID: 26980820 PMCID: PMC4785471 DOI: 10.3945/an.115.010397] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cardiovascular disease (CVD) is the leading cause of death in the United States. Although the role of habitual lifestyle factors such as physical activity and dietary patterns in increasing CVD risk has long been appreciated, less is known about how acute daily activities may cumulatively contribute to long-term disease risk. Here, the term acute refers to metabolic responses occurring in a short period of time after eating, and the goal of this article is to review recently identified stressors that can occur after meals and during the sleep-wake cycle to affect macronutrient metabolism. It is hypothesized that these events, when repeated on a regular basis, contribute to the observed long-term behavioral risks identified in population studies. In this regard, developments in research methods have supported key advancements in 3 fields of macronutrient metabolism. The first of these research areas is the focus on the immediate postmeal metabolism, spanning from early intestinal adsorptive events to the impact of incretin hormones on these events. The second topic is a focus on the importance of meal components on postprandial vasculature function. Finally, some of the most exciting advances are being made in understanding dysregulation in metabolism early in the day, due to insufficient sleep, that may affect subsequent processing of nutrients throughout the day. Key future research questions are highlighted which will lead to a better understanding of the relations between nocturnal, basal (fasting), and early postmeal events, and aid in the development of optimal sleep and targeted dietary patterns to reduce cardiometabolic risk.
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Affiliation(s)
- Miriam Jacome-Sosa
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO;
| | - Richard S Bruno
- Human Nutrition Program, Department of Human Sciences, The Ohio State University, Columbus, OH
| | - Esra Tasali
- Department of Medicine, The University of Chicago, Chicago, IL
| | - Gary F Lewis
- Banting and Best Diabetes Center and Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, University of Toronto, Toronto, Canada
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36
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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37
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Buttet M, Poirier H, Traynard V, Gaire K, Tran TTT, Sundaresan S, Besnard P, Abumrad NA, Niot I. Deregulated Lipid Sensing by Intestinal CD36 in Diet-Induced Hyperinsulinemic Obese Mouse Model. PLoS One 2016; 11:e0145626. [PMID: 26727015 PMCID: PMC4703141 DOI: 10.1371/journal.pone.0145626] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/07/2015] [Indexed: 12/28/2022] Open
Abstract
The metabolic syndrome (MetS) greatly increases risk of cardiovascular disease and diabetes and is generally associated with abnormally elevated postprandial triglyceride levels. We evaluated intestinal synthesis of triglyceride-rich lipoproteins (TRL) in a mouse model of the MetS obtained by feeding a palm oil-rich high fat diet (HFD). By contrast to control mice, MetS mice secreted two populations of TRL. If the smaller size population represented 44% of total particles in the beginning of intestinal lipid absorption in MetS mice, it accounted for only 17% after 4 h due to the secretion of larger size TRL. The MetS mice displayed accentuated postprandial hypertriglyceridemia up to 3 h due to a defective TRL clearance. These alterations reflected a delay in lipid induction of genes for key proteins of TRL formation (MTP, L-FABP) and blood clearance (ApoC2). These abnormalities associated with blunted lipid sensing by CD36, which is normally required to optimize jejunal formation of large TRL. In MetS mice CD36 was not downregulated by lipid in contrast to control mice. Treatment of controls with the proteosomal inhibitor MG132, which prevented CD36 downregulation, resulted in blunted lipid-induction of MTP, L-FABP and ApoC2 gene expression, as in MetS mice. Absence of CD36 sensing was due to the hyperinsulinemia in MetS mice. Acute insulin treatment of controls before lipid administration abolished CD36 downregulation, lipid-induction of TRL genes and reduced postprandial triglycerides (TG), while streptozotocin-treatment of MetS mice restored lipid-induced CD36 degradation and TG secretion. In vitro, insulin treatment abolished CD36-mediated up-regulation of MTP in Caco-2 cells. In conclusion, HFD treatment impairs TRL formation in early stage of lipid absorption via insulin-mediated inhibition of CD36 lipid sensing. This impairment results in production of smaller TRL that are cleared slowly from the circulation, which might contribute to the reported association of CD36 variants with MetS risk.
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Affiliation(s)
- Marjorie Buttet
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Hélène Poirier
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Véronique Traynard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Kévin Gaire
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Thi Thu Trang Tran
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Sinju Sundaresan
- Department of Medicine, Gastroenterology Division, University of Michigan, Ann Arbor, Michigan, 48109, United States of America
| | - Philippe Besnard
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
| | - Nada A. Abumrad
- Department of Medicine, Center for Human Nutrition, and Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
| | - Isabelle Niot
- Physiologie de la Nutrition et Toxicologie (NUTox), UMR U866 INSERM/Université de Bourgogne/AgroSup Dijon, F-21000, Dijon, France
- * E-mail:
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38
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Hashimoto S, Mizutani E, Suzuki M, Yoshida A, Naito M. Effects of Aerobic Exercise on Postprandial Carbohydrate and Lipoprotein Metabolism Following Cookie Ingestion in Healthy Young Women. J Nutr Sci Vitaminol (Tokyo) 2015; 61:299-305. [PMID: 26440636 DOI: 10.3177/jnsv.61.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We examined the acute effects of postprandial aerobic exercise on glucose and lipid metabolism following cookie ingestion. Fifteen healthy young women with a sedentary lifestyle, normal weight and apolipoprotein E3/3 participated. After a 12-h overnight fast, each subject ingested a cookie (1.53 g/kg, Meal Test C) and then performed two trials, one with postprandial exercise (E trial) and one without exercise (C trial), in a randomized crossover design. A single 30-min bout of walking exercise was performed 20 min after the cookie intake. Venous blood samples were drawn before (0 h) and 20 min and 1, 2, 4, and 6 h after cookie ingestion. The Δglucose concentration was not significantly different between the two trials, but the Δinsulin concentration at 1 h and the incremental area under the curve (IAUC) (0-2 h)-insulin in the E trial were significantly lower than in the C trial. The ratio of glucose/insulin at 1 h was significantly higher in the E trial than in the C trial. The ΔTG, ΔRLP-TG, ΔapoB48 and ΔRemL-C concentrations at 1 h in the E trial were significantly higher than in the C trial. The IAUC (0-2 h)-apoB48 in the E trial was significantly larger than in the C trial. Postprandial exercise showed an insulin-sparing effect following the cookie ingestion by increasing insulin sensitivity. However, postprandial exercise transiently stimulated the secretion of exogenous apoB48-containing lipoprotein during the early period, and no further effects were observed. These results suggest that postprandial aerobic exercise is effective for the promotion of postprandial carbohydrate metabolism, but not lipidemia.
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Affiliation(s)
- Sayuki Hashimoto
- Division of Nutrition & Health, School & Graduate School of Life Studies, Sugiyama Jogakuen University
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Hsieh J, Trajcevski KE, Farr SL, Baker CL, Lake EJ, Taher J, Iqbal J, Hussain MM, Adeli K. Glucagon-Like Peptide 2 (GLP-2) Stimulates Postprandial Chylomicron Production and Postabsorptive Release of Intestinal Triglyceride Storage Pools via Induction of Nitric Oxide Signaling in Male Hamsters and Mice. Endocrinology 2015; 156:3538-47. [PMID: 26132919 DOI: 10.1210/en.2015-1110] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The intestinal overproduction of apolipoprotein B48 (apoB48)-containing chylomicron particles is a common feature of diabetic dyslipidemia and contributes to cardiovascular risk in insulin resistant states. We previously reported that glucagon-like peptide-2 (GLP-2) is a key endocrine stimulator of enterocyte fat absorption and chylomicron output in the postprandial state. GLP-2's stimulatory effect on chylomicron production in the postabsorptive state has been confirmed in human studies. The mechanism by which GLP-2 regulates chylomicron production is unclear, because its receptor is not expressed on enterocytes. We provide evidence for a key role of nitric oxide (NO) in mediating the stimulatory effects of GLP-2 during the postprandial and postabsorptive periods. Intestinal chylomicron production was assessed in GLP-2-treated hamsters administered the pan-specific NO synthase (NOS) inhibitor L-N(G)-nitroarginine methyl ester (L-NAME), and in GLP-2-treated endothelial NOS knockout mice. L-NAME blocked GLP-2-stimulated apoB48 secretion and reduced triglycerides (TGs) in the TG-rich lipoprotein (TRL) fraction of the plasma in the postprandial state. Endothelial NOS-deficient mice were resistant to GLP-2 stimulation and secreted fewer large apoB48-particles. When TG storage pools were allowed to accumulate, L-NAME mitigated the GLP-2-mediated increase in TRL-TG, suggesting that NO is required for early mobilization and secretion of stored TG and preformed chylomicrons. Importantly, the NO donor S-nitroso-L-glutathione was able to elicit an increase in TRL-TG in vivo and stimulate chylomicron release in vitro in primary enterocytes. We describe a novel role for GLP-2-mediated NO-signaling as a critical regulator of intestinal lipid handling and a potential contributor to postprandial dyslipidemia.
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Affiliation(s)
- Joanne Hsieh
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Karin E Trajcevski
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Sarah L Farr
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Christopher L Baker
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Elizabeth J Lake
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Jennifer Taher
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Jahangir Iqbal
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Mahmood M Hussain
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
| | - Khosrow Adeli
- Molecular Structure and Function (J.H., K.E.T., S.L.F., C.L.B., E.J.L., J.T., K.A.), Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8; Departments of Biochemistry (J.H., K.E.T., K.A.) and Laboratory Medicine and Pathobiology (S.L.F., J.T., K.A.), University of Toronto, Toronto, Ontario, Canada, M5S 1A8; and State University of New York Downstate Medical Center (J.I., M.H.H.), Brooklyn, New York 11203
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40
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Xiao C, Dash S, Morgantini C, Adeli K, Lewis GF. Gut Peptides Are Novel Regulators of Intestinal Lipoprotein Secretion: Experimental and Pharmacological Manipulation of Lipoprotein Metabolism. Diabetes 2015; 64:2310-8. [PMID: 26106188 DOI: 10.2337/db14-1706] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Individuals with metabolic syndrome and frank type 2 diabetes are at increased risk of atherosclerotic cardiovascular disease, partially due to the presence of lipid and lipoprotein abnormalities. In these conditions, the liver and intestine overproduce lipoprotein particles, exacerbating the hyperlipidemia of fasting and postprandial states. Incretin-based, antidiabetes therapies (i.e., glucagon-like peptide [GLP]-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) have proven efficacy for the treatment of hyperglycemia. Evidence is accumulating that these agents also improve fasting and postprandial lipemia, the latter more significantly than the former. In contrast, the gut-derived peptide GLP-2, cosecreted from intestinal L cells with GLP-1, has recently been demonstrated to enhance intestinal lipoprotein release. Understanding the roles of these emerging regulators of intestinal lipoprotein secretion may offer new insights into the regulation of intestinal lipoprotein assembly and secretion and provide new opportunities for devising novel strategies to attenuate hyperlipidemia, with the potential for cardiovascular disease reduction.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Satya Dash
- Departments of Medicine and Physiology and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Cecilia Morgantini
- Departments of Medicine and Physiology and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Khosrow Adeli
- Program in Molecular Structure & Function, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology and Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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41
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Abstract
Dietary lipids are efficiently absorbed by the small intestine, incorporated into triglyceride-rich lipoproteins (chylomicrons), and transported in the circulation to various tissues. Intestinal lipid absorption and mobilization and chylomicron synthesis and secretion are highly regulated processes. Elevated chylomicron production rate contributes to the dyslipidemia seen in common metabolic disorders such as insulin-resistant states and type 2 diabetes and likely increases the risk for atherosclerosis seen in these conditions. An in-depth understanding of the regulation of chylomicron production may provide leads for the development of drugs that could be of therapeutic utility in the prevention of dyslipidemia and atherosclerosis. Chylomicron secretion is subject to regulation by various factors, including diet, body weight, genetic variants, hormones, nutraceuticals, medications, and emerging interventions such as bariatric surgical procedures. In this review we discuss the regulation of chylomicron production, mechanisms that underlie chylomicron dysregulation, and potential avenues for future research.
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Affiliation(s)
- Satya Dash
- Departments of Medicine and Physiology and the Banting & Best Diabetes Centre, University of Toronto, Toronto, Ontario, M5G 2C4 Canada;
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42
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Han C, Wei S, He F, Liu D, Wan H, Liu H, Li L, Xu H, Du X, Xu F. The Regulation of Lipid Deposition by Insulin in Goose Liver Cells Is Mediated by the PI3K-AKT-mTOR Signaling Pathway. PLoS One 2015; 10:e0098759. [PMID: 25945932 PMCID: PMC4422626 DOI: 10.1371/journal.pone.0098759] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 05/06/2014] [Indexed: 11/23/2022] Open
Abstract
Background We previously showed that the fatty liver formations observed in overfed geese are accompanied by the activation of the PI3K-Akt-mTOR pathway and an increase in plasma insulin concentrations. Recent studies have suggested a crucial role for the PI3K-Akt-mTOR pathway in regulating lipid metabolism; therefore, we hypothesized that insulin affects goose hepatocellular lipid metabolism through the PI3K-Akt-mTOR signaling pathway. Methods Goose primary hepatocytes were isolated and treated with serum-free media supplemented with PI3K-Akt-mTOR pathway inhibitors (LY294002, rapamycin, and NVP-BEZ235, respectively) and 50 or 150 nmol/L insulin. Results Insulin induced strong effects on lipid accumulation as well as the mRNA and protein levels of genes involved in lipogenesis, fatty acid oxidation, and VLDL-TG assembly and secretion in primary goose hepatocytes. The stimulatory effect of insulin on lipogenesis was significantly decreased by treatment with PI3K-Akt-mTOR inhibitors. These inhibitors also rescued the insulin-induced down-regulation of fatty acid oxidation and VLDL-TG assembly and secretion. Conclusion These findings suggest that the stimulatory effect of insulin on lipid deposition is mediated by PI3K-Akt-mTOR regulation of lipogenesis, fatty acid oxidation, and VLDL-TG assembly and secretion in goose hepatocytes.
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Affiliation(s)
- Chunchun Han
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
- * E-mail:
| | - Shouhai Wei
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Fang He
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Dandan Liu
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Huofu Wan
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Hehe Liu
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Liang Li
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Hongyong Xu
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Xiaohui Du
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
| | - Feng Xu
- Institute of Animal Breeding & Genetic, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China
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Abstract
Hypertriglyceridemia (HTG) is a highly prevalent condition that is associated with increased cardiovascular disease risk. HTG may arise as a result of defective metabolism of triglyceride-rich lipoproteins and their remnants, ie, impaired clearance, or increased production, or both. Current categorization of HTG segregates primary and secondary cases, implying genetic and nongenetic causes for each category. Many common and rare variants of the genes encoding factors involved in these pathways have been identified. Although monogenic forms of HTG do occur, most cases are polygenic and often coexist with nongenetic conditions. Cumulative, multiple genetic variants can increase the risks for HTG, whereas environmental and lifestyle factors can force expression of a dyslipidemic phenotype in a genetically susceptible person. HTG states are therefore best viewed as a complex phenotype resulting from the interaction of cumulated multiple susceptibility genes and environmental stressors. In view of the heterogeneity of the HTG states, the absence of a unifying metabolic or genetic abnormality, overlap with the metabolic syndrome and other features of insulin resistance, and evidence in some patients that accumulation of numerous small-effect genetic variants determines whether an individual is susceptible to HTG only or to HTG plus elevated low-density lipoprotein cholesterol, we propose that the diagnosis of primary HTG and further delineation of familial combined hyperlipidemia from familial HTG is neither feasible nor clinically relevant at the present time. The hope is that with greater understanding of genetic and environmental causes and their interaction, therapy can be intelligently targeted in the future.
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Affiliation(s)
- Gary F Lewis
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre (G.F.L., C.X.), University of Toronto, Toronto, Ontario, Canada M5G 2C4; and Robarts Research Institute (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5B7
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Dash S, Xiao C, Morgantini C, Connelly PW, Patterson BW, Lewis GF. Glucagon-like peptide-2 regulates release of chylomicrons from the intestine. Gastroenterology 2014; 147:1275-1284.e4. [PMID: 25173752 PMCID: PMC4316201 DOI: 10.1053/j.gastro.2014.08.037] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND & AIMS The intestine efficiently incorporates and rapidly secretes dietary fat as chylomicrons (lipoprotein particles comprising triglycerides, phospholipids, cholesterol, and proteins) that contain the apolipoprotein isoform apoB-48. The gut can store lipids for many hours after their ingestion, and release them in chylomicrons in response to oral glucose, sham feeding, or unidentified stimuli. The gut hormone glucagon-like peptide-2 (GLP-2) facilitates intestinal absorption of lipids, but its role in chylomicron secretion in human beings is unknown. METHODS We performed a randomized, single-blind, cross-over study, with 2 study visits 4 weeks apart, to assess the effects of GLP-2 administration on triglyceride-rich lipoprotein (TRL) apoB-48 in 6 healthy men compared with placebo. Subjects underwent constant intraduodenal feeding, with a pancreatic clamp and primed constant infusion of deuterated leucine. In a separate randomized, single-blind, cross-over validation study, 6 additional healthy men ingested a high-fat meal containing retinyl palmitate and were given either GLP-2 or placebo 7 hours later with measurement of TRL triglyceride, TRL retinyl palmitate, and TRL apoB-48 levels. RESULTS GLP-2 administration resulted in a rapid (within 30 minutes) and transient increase in the concentration of TRL apoB-48, compared with placebo (P = .03). Mathematic modeling of stable isotope enrichment and the mass of the TRL apoB-48 suggested that the increase resulted from the release of stored, presynthesized apoB-48 from the gut. In the validation study, administration of GLP-2 at 7 hours after the meal, in the absence of additional food intake, robustly increased levels of TRL triglycerides (P = .007), TRL retinyl palmitate (P = .002), and TRL apoB-48 (P = .04) compared with placebo. CONCLUSIONS Administration of GLP-2 to men causes the release of chylomicrons that comprise previously synthesized and stored apoB-48 and lipids. This transiently increases TRL apoB-48 levels compared with placebo. Clinical trials number at www.clinicaltrials.gov: NCT 01958775.
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Affiliation(s)
- Satya Dash
- Department of Medicine, Department of Physiology, Banting and Best Diabetes Centre, Canada
,Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Changting Xiao
- Department of Medicine, Department of Physiology, Banting and Best Diabetes Centre, Canada
,Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Cecilia Morgantini
- Department of Medicine, Department of Physiology, Banting and Best Diabetes Centre, Canada
,Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Philip W. Connelly
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
,Keenan Research Centre for Biomedical Science of St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Bruce W. Patterson
- Center for Human Nutrition, Department of Internal Medicine, Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, Missouri
| | - Gary F. Lewis
- Department of Medicine, Department of Physiology, Banting and Best Diabetes Centre, Canada
,Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Werner C, Filmer A, Fritsch M, Groenewold S, Gräber S, Böhm M, Laufs U. Risk prediction with triglycerides in patients with stable coronary disease on statin treatment. Clin Res Cardiol 2014; 103:984-97. [PMID: 25012240 DOI: 10.1007/s00392-014-0740-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND The aim of the prospective Homburg Cream and Sugar study was to analyze the role of fasting and postprandial serum triglycerides (TG) as risk modifiers in patients with coronary artery disease (CAD). METHODS AND RESULTS A sequential oral triglyceride and glucose tolerance test was developed to obtain standardized measurements of postprandial TG kinetics and glucose in 514 consecutive patients with stable CAD confirmed by angiography (95% were treated with a statin). Fasting and postprandial TG predicted the primary outcome measure of cardiovascular death and hospitalizations after 48 months follow-up (fasting TG >150 vs. <106 mg/dl: Hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.31-2.45, p = 0.0001; area under the curve >1120 vs. <750 mg/dl/5 hr: HR 1.78, 95% CI 1.29-2.45, p = 0.0003). Parameters of the postprandial TG increase did not improve risk prediction compared to fasting TG. The number of cardiovascular deaths and myocardial infarctions was higher in the upper tertile of fasting TG (HR 1.79, 95%-CI 1.04-3.09, p = 0.03). Risk prediction by TG was independent of traditional risk factors, medication, glucose metabolism, LDL- and HDL-cholesterol. Total cholesterol, LDL- and HDL-cholesterol concentrations were not associated with the primary outcome. CONCLUSIONS Fasting serum triglycerides >150 mg/dl independently predict cardiovascular events in patients with coronary artery disease on guideline-recommended medication. Assessment of postprandial TG does not improve risk prediction compared to fasting TG in these patients.
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Affiliation(s)
- Christian Werner
- Klinik für Innere Medizin III (Kardiologie, Angiologie und Internistische Intensivmedizin), Universitätsklinikum des Saarlandes, 66421, Homburg/Saar, Germany,
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Xiao C, Dash S, Morgantini C, Patterson BW, Lewis GF. Sitagliptin, a DPP-4 inhibitor, acutely inhibits intestinal lipoprotein particle secretion in healthy humans. Diabetes 2014; 63:2394-401. [PMID: 24584549 PMCID: PMC4066342 DOI: 10.2337/db13-1654] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The dipeptidyl peptidase-4 inhibitor sitagliptin, an antidiabetic agent, which lowers blood glucose levels, also reduces postprandial lipid excursion after a mixed meal. The underlying mechanism of this effect, however, is not clear. This study examined the production and clearance of triglyceride-rich lipoprotein particles from the liver and intestine in healthy volunteers in response to a single oral dose of sitagliptin. Using stable isotope tracer techniques and with control of pancreatic hormone levels, the kinetics of lipoprotein particles of intestinal and hepatic origin were measured. Compared with placebo, sitagliptin decreased intestinal lipoprotein concentration by inhibiting particle production, independent of changes in pancreatic hormones, and circulating levels of glucose and free fatty acids. Fractional clearance of particles of both intestinal and hepatic origin, and production of particles of hepatic origin, were not affected. This pleiotropic effect of sitagliptin may explain the reduction in postprandial lipemia seen in clinical trials of this agent and may provide metabolic benefits beyond lowering of glucose levels.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Satya Dash
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Cecilia Morgantini
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Bruce W Patterson
- Center for Human Nutrition, Department of Internal Medicine, Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Jacome-Sosa MM, Parks EJ. Fatty acid sources and their fluxes as they contribute to plasma triglyceride concentrations and fatty liver in humans. Curr Opin Lipidol 2014; 25:213-20. [PMID: 24785962 DOI: 10.1097/mol.0000000000000080] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Different sources of fatty acids (FA) used for VLDL-triglyceride synthesis include dietary FA that clear to the liver via chylomicron uptake, FA synthesized de novo in the liver from carbohydrates, nonesterified fatty acids derived from adipose tissue, nonesterified fatty acids derived from the spillover of chylomicron-triglyceride in the fasted and fed states, and FA stored in liver lipid droplets. RECENT FINDINGS Data have amassed on the contributions of each of these sources to liver-triglyceride accrual, VLDL-triglyceride synthesis, and hypertriglyceridemia. Discussed here is the timing of use of FA from each of these sources for synthesis of VLDL-triglyceride. Secondly, as all of these FA sources have been shown to contribute significantly to nonalcoholic fatty liver disease (NAFLD), data are presented demonstrating how poor handling of FA and glucose in the periphery can contribute to NAFLD. Lastly, we highlight how the stress of excess FA availability on the liver can be corrected by reduction of dietary intake of sugars and fats, weight loss, and increased physical activity. SUMMARY A better understanding of how lifestyle factors improve FA flux will aid in the development of improved treatments for the devastating condition of NAFLD.
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Affiliation(s)
- M Miriam Jacome-Sosa
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, USA
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Xiao C, Dash S, Morgantini C, Lewis GF. New and emerging regulators of intestinal lipoprotein secretion. Atherosclerosis 2014; 233:608-615. [PMID: 24534456 DOI: 10.1016/j.atherosclerosis.2013.12.047] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/12/2013] [Accepted: 12/31/2013] [Indexed: 12/25/2022]
Abstract
Overproduction of hepatic apoB100-containing VLDL particles has been well documented in animal models and in humans with insulin resistance such as the metabolic syndrome and type 2 diabetes, and contributes to the typical dyslipidemia of these conditions. In addition, postprandial hyperlipidemia and elevated plasma concentrations of intestinal apoB48-containing chylomicron and chylomicron remnant particles have been demonstrated in insulin resistant states. Intestinal lipoprotein production is primarily determined by the amount of fat ingested and absorbed. Until approximately 10 years ago, however, relatively little attention was paid to the role of the intestine itself in regulating the production of triglyceride-rich lipoproteins (TRL) and its dysregulation in pathological states such as insulin resistance. We and others have shown that insulin resistant animal models and humans are characterized by overproduction of intestinal apoB48-containing lipoproteins. Whereas various factors are known to regulate hepatic lipoprotein particle production, less is known about factors that regulate the production of intestinal lipoprotein particles. Monosacharides, plasma free fatty acids (FFA), resveratrol, intestinal peptides (e.g. GLP-1 and GLP-2), and pancreatic hormones (e.g. insulin) have recently been shown to be important regulators of intestinal lipoprotein secretion. Available evidence in humans and animal models strongly supports the concept that the small intestine is not merely an absorptive organ but rather plays an active role in regulating the rate of production of chylomicrons in fed and fasting states. Metabolic signals in insulin resistance and type 2 diabetes and in some cases an aberrant intestinal response to these factors contribute to the enhanced formation and secretion of TRL. Understanding the regulation of intestinal lipoprotein production is imperative for the development of new therapeutic strategies for the prevention and treatment of dyslipidemia. Here we review recent developments in this field and present evidence that intestinal lipoprotein production is a process with metabolic plasticity and that modulation of intestinal lipoprotein secretion may be a feasible therapeutic strategy in the treatment of dyslipidemia and possibly prevention of atherosclerosis.
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Affiliation(s)
- Changting Xiao
- Department of Medicine, University of Toronto, Canada; Department of Physiology, University of Toronto, Canada; Banting and Best Diabetes Centre, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada
| | - Satya Dash
- Department of Medicine, University of Toronto, Canada; Department of Physiology, University of Toronto, Canada; Banting and Best Diabetes Centre, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada
| | - Cecilia Morgantini
- Department of Medicine, University of Toronto, Canada; Department of Physiology, University of Toronto, Canada; Banting and Best Diabetes Centre, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada
| | - Gary F Lewis
- Department of Medicine, University of Toronto, Canada; Department of Physiology, University of Toronto, Canada; Banting and Best Diabetes Centre, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada.
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Shojaee-Moradie F, Ma Y, Lou S, Hovorka R, Umpleby AM. Prandial hypertriglyceridemia in metabolic syndrome is due to an overproduction of both chylomicron and VLDL triacylglycerol. Diabetes 2013; 62:4063-9. [PMID: 23990358 PMCID: PMC3837057 DOI: 10.2337/db13-0935] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The aim was to determine whether fed VLDL and chylomicron (CM) triacylglycerol (TAG) production rates are elevated in metabolic syndrome (MetS). Eight men with MetS (BMI 29.7 ± 1.1) and eight lean age-matched healthy men (BMI 23.1 ± 0.4) were studied using a frequent feeding protocol. After 4 h of feeding, an intravenous bolus of (2)H5-glycerol was administered to label VLDL1, VLDL2, and TAG. (13)C-glycerol tripalmitin was administered orally as an independent measure of CM TAG metabolism. Hepatic and intestinal lipoproteins were separated by an immunoaffinity method. In MetS, fed TAG and the increment in TAG from fasting to feeding were higher (P = 0.03 and P = 0.04, respectively) than in lean men. Fed CM, VLDL1, and VLDL2 TAG pool sizes were higher (P = 0.006, P = 0.03, and P < 0.02, respectively), and CM, VLDL1, and VLDL2 TAG production rates were higher (P < 0.002, P < 0.05, and P = 0.06, respectively) than in lean men. VLDL1, VLDL2, and CM TAG clearance rates were not different between groups. In conclusion, prandial hypertriglyceridemia in men with MetS was due to an increased production rate of both VLDL and CM TAG. Since both groups received identical meals, this suggests that in MetS the intestine is synthesizing more TAG de novo for export in CMs.
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Affiliation(s)
- Fariba Shojaee-Moradie
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, U.K
| | - Yuying Ma
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, U.K
| | - Shaoying Lou
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, U.K
| | - Roman Hovorka
- Diabetes Modelling Group, Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - A. Margot Umpleby
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, U.K
- Corresponding author: A. Margot Umpleby,
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Couture P, Tremblay AJ, Kelly I, Lemelin V, Droit A, Lamarche B. Key intestinal genes involved in lipoprotein metabolism are downregulated in dyslipidemic men with insulin resistance. J Lipid Res 2013; 55:128-37. [PMID: 24142110 DOI: 10.1194/jlr.m040071] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Insulin resistance (IR) is associated with elevated plasma levels of triglyceride-rich lipoproteins (TRLs) of intestinal origin. However, the mechanisms underlying the overaccumulation of apolipoprotein (apo)B-48-containing TRLs in individuals with IR are not yet fully understood. This study examined the relationships between apoB-48-containing TRL kinetics and the expression of key intestinal genes and proteins involved in lipid/lipoprotein metabolism in 14 obese nondiabetic men with IR compared with 10 insulin-sensitive (IS) men matched for waist circumference. The in vivo kinetics of TRL apoB-48 were assessed using a primed-constant infusion of L-[5,5,5-D₃]leucine for 12 h with the participants in a constantly fed state. The expression of key intestinal genes and proteins involved in lipid/lipoprotein metabolism was assessed by performing real-time PCR quantification and LC-MS/MS on duodenal biopsy specimens. The TRL apoB-48 pool size and production rate were 102% (P < 0.0001) and 87% (P = 0.01) greater, respectively, in the men with IR versus the IS men. On the other hand, intestinal mRNA levels of sterol regulatory element binding factor-2, hepatocyte nuclear factor-4α, and microsomal triglyceride transfer protein were significantly lower in the men with IR than in the IS men. These data indicate that IR is associated with intestinal overproduction of lipoproteins and significant downregulation of key intestinal genes involved in lipid/lipoprotein metabolism.
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Affiliation(s)
- Patrick Couture
- Institute of Nutrition and Functional Foods Centre Hospitalier de l'Université Laval (CHUL) Research Centre
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