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Nahle A, Joseph YD, Pereira S, Mori Y, Poon F, Ghadieh HE, Ivovic A, Desai T, Ghanem SS, Asalla S, Muturi HT, Jentz EM, Joseph JW, Najjar SM, Giacca A. Nicotinamide Mononucleotide Prevents Free Fatty Acid-Induced Reduction in Glucose Tolerance by Decreasing Insulin Clearance. Int J Mol Sci 2021; 22:ijms222413224. [PMID: 34948019 PMCID: PMC8709165 DOI: 10.3390/ijms222413224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 11/24/2022] Open
Abstract
The NAD-dependent deacetylase SIRT1 improves β cell function. Accordingly, nicotinamide mononucleotide (NMN), the product of the rate-limiting step in NAD synthesis, prevents β cell dysfunction and glucose intolerance in mice fed a high-fat diet. The current study was performed to assess the effects of NMN on β cell dysfunction and glucose intolerance that are caused specifically by increased circulating free fatty acids (FFAs). NMN was intravenously infused, with or without oleate, in C57BL/6J mice over a 48-h-period to elevate intracellular NAD levels and consequently increase SIRT1 activity. Administration of NMN in the context of elevated plasma FFA levels considerably improved glucose tolerance. This was due not only to partial protection from FFA-induced β cell dysfunction but also, unexpectedly, to a significant decrease in insulin clearance. However, in conditions of normal FFA levels, NMN impaired glucose tolerance due to decreased β cell function. The presence of this dual action of NMN suggests caution in its proposed therapeutic use in humans.
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Affiliation(s)
- Ashraf Nahle
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Yemisi Deborah Joseph
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Sandra Pereira
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Yusaku Mori
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
- Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Shinagawa, Tokyo 142-0064, Japan
| | - Frankie Poon
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Hilda E. Ghadieh
- Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43606, USA; (H.E.G.); (S.S.G.); (S.M.N.)
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (S.A.); (H.T.M.)
| | - Aleksandar Ivovic
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Tejas Desai
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
| | - Simona S. Ghanem
- Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43606, USA; (H.E.G.); (S.S.G.); (S.M.N.)
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (S.A.); (H.T.M.)
| | - Suman Asalla
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (S.A.); (H.T.M.)
| | - Harrison T. Muturi
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (S.A.); (H.T.M.)
| | - Emelien M. Jentz
- School of Pharmacy, University of Waterloo, Kitchener, ON N2G 1C5, Canada; (E.M.J.); (J.W.J.)
| | - Jamie W. Joseph
- School of Pharmacy, University of Waterloo, Kitchener, ON N2G 1C5, Canada; (E.M.J.); (J.W.J.)
| | - Sonia M. Najjar
- Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43606, USA; (H.E.G.); (S.S.G.); (S.M.N.)
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (S.A.); (H.T.M.)
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
| | - Adria Giacca
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; (A.N.); (Y.D.J.); (S.P.); (Y.M.); (F.P.); (A.I.); (T.D.)
- Banting and Best Diabetes Centre, University of Toronto, Toronto, ON M5G 2C4, Canada
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A1, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence:
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Kraft G, Coate KC, Smith M, Farmer B, Scott M, Cherrington AD, Edgerton DS. The Importance of the Mechanisms by Which Insulin Regulates Meal-Associated Liver Glucose Uptake in the Dog. Diabetes 2021; 70:1292-1302. [PMID: 33757993 PMCID: PMC8275892 DOI: 10.2337/db20-1271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/18/2021] [Indexed: 12/17/2022]
Abstract
Hepatic glucose uptake (HGU) is critical for maintaining normal postprandial glucose metabolism. Insulin is clearly a key regulator of HGU, but the physiologic mechanisms by which it acts have yet to be established. This study sought to determine the mechanisms by which insulin regulates liver glucose uptake under postprandial-like conditions (hyperinsulinemia, hyperglycemia, and a positive portal vein-to-arterial glucose gradient). Portal vein insulin infusion increased hepatic insulin levels fivefold in healthy dogs. In one group (n = 7), the physiologic response was allowed to fully occur, while in another (n = 7), insulin's indirect hepatic effects, occurring secondary to its actions on adipose tissue, pancreas, and brain, were blocked. This was accomplished by infusing triglyceride (intravenous), glucagon (portal vein), and inhibitors of brain insulin action (intracerebroventricular) to prevent decreases in plasma free fatty acids or glucagon, while blocking increased hypothalamic insulin signaling for 4 h. In contrast to the indirect hepatic effects of insulin, which were previously shown capable of independently generating a half-maximal stimulation of HGU, direct hepatic insulin action was by itself able to fully stimulate HGU. This suggests that under hyperinsulinemic/hyperglycemic conditions insulin's indirect effects are redundant to direct engagement of hepatocyte insulin receptors.
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Affiliation(s)
- Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Katie C Coate
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Melanie Scott
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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Foley KP, Zlitni S, Duggan BM, Barra NG, Anhê FF, Cavallari JF, Henriksbo BD, Chen CY, Huang M, Lau TC, Plante R, Schwab M, Marette A, Schertzer JD. Gut microbiota impairs insulin clearance in obese mice. Mol Metab 2020; 42:101067. [PMID: 32860984 PMCID: PMC7522491 DOI: 10.1016/j.molmet.2020.101067] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/20/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
Objective Hyperinsulinemia can be both a cause and consequence of obesity and insulin resistance. Hyperinsulinemia can result from increased insulin secretion and/or reduced insulin clearance. While many studies have focused on mechanisms triggering insulin secretion during obesity, the triggers for changes in insulin clearance during obesity are less defined. In this study, we investigated the role of the microbiota in regulating insulin clearance during diet-induced obesity. Methods Blood glucose and insulin clearance were tested in conventional male mice treated with antibiotics and germ-free mice colonized with microbes from mice that were fed a control (chow) diet or an obesogenic high-fat diet (HFD). The composition of the fecal microbiota was analyzed using 16S rRNA sequencing. Results Short-term HFD feeding and aging did not alter insulin clearance in the mice. Oral antibiotics mitigated impaired blood insulin clearance in the mice fed an HFD for 12 weeks or longer. Germ-free mice colonized with microbes from HFD-fed donor mice had impaired insulin but not C-peptide clearance. Microbe-transmissible insulin clearance impairment was only observed in germ-free mice after more than 6 weeks post-colonization upon HFD feeding. Five bacterial taxa predicted >90% of the variance in insulin clearance. Mechanistically, impaired insulin clearance was associated with lower levels of hepatic Ceacam-1 but increased liver and skeletal muscle insulin-degrading enzyme (IDE) activity. Conclusions Gut microbes regulate insulin clearance during diet-induced obesity. A small cluster of microbes or their metabolites may be targeted for mitigating defects in insulin clearance and hyperinsulinemia during the progression of obesity and type 2 diabetes. Obesity impairs insulin clearance in mice, which is mitigated by antibiotics. The gut microbiota contributes to impaired insulin but not C-peptide clearance. The gut microbiota is a stand-alone factor that impairs insulin clearance. A cluster of related bacteria predict >90% of the variance in insulin clearance. Impaired insulin clearance is associated with lower hepatic Ceacam-1.
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Affiliation(s)
- Kevin P Foley
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Soumaya Zlitni
- Departments of Genetics and Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Brittany M Duggan
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Nicole G Barra
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Fernando F Anhê
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Joseph F Cavallari
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Brandyn D Henriksbo
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Cassandra Y Chen
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Michael Huang
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Trevor C Lau
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - Roxanne Plante
- Quebec Heart and Lung Institute Research Center, Faculty of Medicine, Laval University, Quebec City, Quebec, G1V 4G5, Canada
| | - Michael Schwab
- Quebec Heart and Lung Institute Research Center, Faculty of Medicine, Laval University, Quebec City, Quebec, G1V 4G5, Canada
| | - André Marette
- Quebec Heart and Lung Institute Research Center, Faculty of Medicine, Laval University, Quebec City, Quebec, G1V 4G5, Canada
| | - Jonathan D Schertzer
- Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute McMaster University, Hamilton, Ontario, L8N 3Z5, Canada.
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Najjar SM, Perdomo G. Hepatic Insulin Clearance: Mechanism and Physiology. Physiology (Bethesda) 2019; 34:198-215. [PMID: 30968756 DOI: 10.1152/physiol.00048.2018] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Upon its secretion from pancreatic β-cells, insulin reaches the liver through the portal circulation to exert its action and eventually undergo clearance in the hepatocytes. In addition to insulin secretion, hepatic insulin clearance regulates the homeostatic level of insulin that is required to reach peripheral insulin target tissues to elicit proper insulin action. Receptor-mediated insulin uptake followed by its degradation constitutes the basic mechanism of insulin clearance. Upon its phosphorylation by the insulin receptor tyrosine kinase, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) takes part in the insulin-insulin receptor complex to increase the rate of its endocytosis and targeting to the degradation pathways. This review summarizes how this process is regulated and how it is associated with insulin-degrading enzyme in the liver. It also discusses the physiological implications of impaired hepatic insulin clearance: Whereas reduced insulin clearance cooperates with increased insulin secretion to compensate for insulin resistance, it can also cause hepatic insulin resistance. Because chronic hyperinsulinemia stimulates hepatic de novo lipogenesis, impaired insulin clearance also causes hepatic steatosis. Thus impaired insulin clearance can underlie the link between hepatic insulin resistance and hepatic steatosis. Delineating these regulatory pathways should lead to building more effective therapeutic strategies against metabolic syndrome.
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Affiliation(s)
- Sonia M Najjar
- Department of Biomedical Sciences, Ohio University , Athens, Ohio.,Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
| | - Germán Perdomo
- Departamento de Ciencias de la Salud, Universidad de Burgos , Burgos , Spain
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Elseweidy MM, Amin RS, Atteia HH, Aly MA. Nigella sativa Oil and Chromium Picolinate Ameliorate Fructose-Induced Hyperinsulinemia by Enhancing Insulin Signaling and Suppressing Insulin-Degrading Enzyme in Male Rats. Biol Trace Elem Res 2018; 184:119-126. [PMID: 28975521 DOI: 10.1007/s12011-017-1167-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/25/2017] [Indexed: 02/05/2023]
Abstract
In vivo and in vitro studies suggested that chromium enhances insulin sensitivity by promoting insulin receptor signaling. However, its effect on insulin clearance has not been yet identified. Nigella sativa, a widely used spice, possesses an antidiabetic activity. We, therefore, hypothesized that chromium picolinate may alter insulin clearance by modulating insulin-degrading enzyme (IDE) in insulin-resistant rats. We evaluated also the effect of Nigella sativa oil on insulin signaling and degradation with respect to chromium picolinate. To assess these hypotheses, insulin resistance was induced in 30 male Wistar albino rats through daily oral administration of high-fructose water (HFW, 20% w/v) for 45 days. These rats were then divided into three groups (n = 10/group). They were given either no treatment (control group) or Nigella sativa oil (500 mg/kg bw/day) or chromium picoloinate (200 μg/kg bw/day) orally along with HFW (20% w/v) for 45 days. Nigella sativa oil or chromium picolinate concurrent administration with HFW significantly decreased body weight, serum lipids, glucagon, insulin resistance, and hepatic IDE level but increased its mRNA expression and insulin receptor phosphorlyation as well as high-density lipoprotein cholesterol (HDL-C) level as compared to control group values, suggesting their potential as modulators for insulin signaling and clearance. However, Nigella sativa oil exerted better improvement in feeding efficacy ratio as well as the levels of glucagon, insulin, insulin resistance, hepatic IDE level and insulin receptor phosphorylation than chromium picolinate, suggesting its greater insulin sensitizing capacity. Our data, for the first time, prove that Nigella sativa oil and chromium picolinate monotherapy can reduce fructose-induced insulin resistance by reduction of hepatic IDE protein and activation of insulin receptor signaling.
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Affiliation(s)
- Mohamed Mahmoud Elseweidy
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Sharkia, 44519, Egypt.
| | - Rawia Sarhan Amin
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Sharkia, 44519, Egypt
| | - Hebatallah Husseini Atteia
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Sharkia, 44519, Egypt
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Tabuk, Tabuk, Kingdom of Saudi Arabia
| | - Maha Abdo Aly
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Sharkia, 44519, Egypt
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Williams AS, Trefts E, Lantier L, Grueter CA, Bracy DP, James FD, Pozzi A, Zent R, Wasserman DH. Integrin-Linked Kinase Is Necessary for the Development of Diet-Induced Hepatic Insulin Resistance. Diabetes 2017; 66:325-334. [PMID: 27899483 PMCID: PMC5248997 DOI: 10.2337/db16-0484] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 11/17/2016] [Indexed: 12/17/2022]
Abstract
The liver extracellular matrix (ECM) expands with high-fat (HF) feeding. This finding led us to address whether receptors for the ECM, integrins, are key to the development of diet-induced hepatic insulin resistance. Integrin-linked kinase (ILK) is a downstream integrin signaling molecule involved in multiple hepatic processes, including those related to differentiation, wound healing, and metabolism. We tested the hypothesis that deletion of ILK in mice on an HF diet would disrupt the ECM-integrin signaling axis, thereby preventing the transformation into the insulin-resistant liver. To determine the role of ILK in hepatic insulin action in vivo, male C57BL/6J ILKlox/lox mice were crossed with Albcre mice to produce a hepatocyte-specific ILK deletion (ILKlox/loxAlbcre). Results from this study show that hepatic ILK deletion has no effect on insulin action in lean mice but sensitizes the liver to insulin during the challenge of HF feeding. This effect corresponds to changes in the expression and activation of key insulin signaling pathways as well as a greater capacity for hepatic mitochondrial glucose oxidation. This demonstrates that ILK contributes to hepatic insulin resistance and highlights the previously undefined role of integrin signaling in the pathogenesis of diet-induced hepatic insulin resistance.
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Affiliation(s)
- Ashley S Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Elijah Trefts
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | - Carrie A Grueter
- Department of Anesthesiology, Vanderbilt University, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Freyja D James
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Ambra Pozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, TN
- Department of Medicine, Veteran Affairs, Nashville, TN
| | - Roy Zent
- Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, TN
- Department of Medicine, Veteran Affairs, Nashville, TN
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
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Elseweidy MM, Amin RS, Atteia HH, Ali MA. Vitamin D3 intake as regulator of insulin degrading enzyme and insulin receptor phosphorylation in diabetic rats. Biomed Pharmacother 2016; 85:155-159. [PMID: 27930980 DOI: 10.1016/j.biopha.2016.11.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/27/2016] [Indexed: 02/08/2023] Open
Abstract
Insulin-degrading enzyme (IDE, insulysin) is a rate-limiting enzyme in the insulin degradation process. It is an intracellular 110-kDa thiol zinc-metalloendopeptidase located in the cytosol, peroxisomes, endosomes and cell surface. IDE catalyzes degradation of several small proteins including insulin, amylin and β-amyloid protein. In addition, insulin clearance was expressed as a target in the treatment of type 2 diabetes given the role of hyperinsulinemia in the pathogenesis of insulin resistance. In this study, fourtyadult male Wistar albino rats were used, thirty rats received 20% fructose in drinking water (HFW) for six weeks to induce diabetes. Subsequently, these rats developed significantly higher body weights, dyslipidemia, hyperglycemia and insulin resistance compared to their controls. Significant increase in the levels of serum glucagon, IDE in liver tissue along with an inhibition of insulin receptor phosphorylation were also observed. Concurrent oral administration of vitamin D3 along with HFW resulted in significant decrease of serum glucose, total cholesterol, triacylglycerol and LDL-C levels. Vitamin D alleviated also insulin resistance, where both IDE, glucagon levels showed significant decrease along with activation of insulin receptor phosphorylation. Normal rats, received vitamin D3 only demonstrated non significant changes of the studied biomarkers. We concluded that vitamin D3 ameliorated insulin resistance and hyperinsulinemia in diabetic rat model received HFW through reduction of IDE and activation of insulin receptor phosphorylation.
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Affiliation(s)
| | - Rawia Sarhan Amin
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Sharkia Gov., Egypt
| | | | - Maha Abdo Ali
- Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Sharkia Gov., Egypt
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Ramakrishnan SK, Russo L, Ghanem SS, Patel PR, Oyarce AM, Heinrich G, Najjar SM. Fenofibrate Decreases Insulin Clearance and Insulin Secretion to Maintain Insulin Sensitivity. J Biol Chem 2016; 291:23915-23924. [PMID: 27662905 DOI: 10.1074/jbc.m116.745778] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/22/2016] [Indexed: 01/18/2023] Open
Abstract
High fat diet reduces the expression of CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1), a transmembrane glycoprotein that promotes insulin clearance and down-regulates fatty acid synthase activity in the liver upon its phosphorylation by the insulin receptor. Because peroxisome proliferator-activated receptor α (PPARα) transcriptionally suppresses CEACAM1 expression, we herein examined whether high fat down-regulates CEACAM1 expression in a PPARα-dependent mechanism. By activating PPARα, the lipid-lowering drug fenofibrate reverses dyslipidemia and improves insulin sensitivity in type 2 diabetes in part by promoting fatty acid oxidation. Despite reducing glucose-stimulated insulin secretion, fenofibrate treatment does not result in insulin insufficiency. To examine whether this is mediated by a parallel decrease in CEACAM1-dependent hepatic insulin clearance pathways, we fed wild-type and Pparα-/- null mice a high fat diet supplemented with either fenofibrate or Wy14643, a selective PPARα agonist, and examined their effect on insulin metabolism and action. We demonstrated that the decrease in insulin secretion by fenofibrate and Wy14643 is accompanied by reduction in insulin clearance in wild-type but not Pparα-/- mice, thereby maintaining normoinsulinemia and insulin sensitivity despite continuous high fat intake. Intact insulin secretion in L-CC1 mice with protected hepatic insulin clearance and CEACAM1 levels provides in vivo evidence that insulin secretion responds to changes in insulin clearance to maintain physiologic insulin and glucose homeostasis. These results also emphasize the relevant role of hepatic insulin extraction in regulating insulin sensitivity.
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Affiliation(s)
- Sadeesh K Ramakrishnan
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614
| | - Lucia Russo
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614
| | - Simona S Ghanem
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614
| | - Payal R Patel
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614
| | - Ana Maria Oyarce
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614.,the Department of Pharmacology and Experimental Therapeutics College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, Ohio 43614, and
| | - Garrett Heinrich
- the Department of Pharmacology and Experimental Therapeutics College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, Ohio 43614, and
| | - Sonia M Najjar
- From the Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio 43614, .,the Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio 45701
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Vogt JA, Domzig C, Wabitsch M, Denzer C. Prehepatic secretion and disposal of insulin in obese adolescents as estimated by three-hour, eight-sample oral glucose tolerance tests. Am J Physiol Endocrinol Metab 2016; 311:E82-94. [PMID: 27143555 DOI: 10.1152/ajpendo.00455.2014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 04/25/2016] [Indexed: 01/10/2023]
Abstract
The body compensates for early-stage insulin resistance by increasing insulin secretion. A reliable and easy-to-use mathematical assessment of insulin secretion and disposal could be a valuable tool for identifying patients at risk for the development of type 2 diabetes. Because the pathophysiology of insulin resistance is incompletely understood, assessing insulin metabolism with minimal assumptions regarding its metabolic regulation is a major challenge. To assess insulin secretion and indexes of insulin disposal, our marginalized and regularized absorption approach (MRA) was applied to a sparse sampling oral glucose tolerance test (OGTT) protocol measuring the insulin and C-peptide concentrations. Identifiability and potential bias of metabolic parameters were estimated from published data with dense sampling. The MRA was applied to OGTT data from 135 obese adolescents to demonstrate its clinical applicability. Individual prehepatic basal and dynamic insulin secretion and clearance levels were determined with a precision and accuracy greater than 10% of the nominal value. The intersubject variability in these parameters was approximately four times higher than the intrasubject variability, and there was a strong negative correlation between prehepatic secretion and plasma clearance of insulin. MRA-based analysis provides reliable estimates of insulin secretion and clearance, thereby enabling detailed glucose homeostasis characterization based on restricted datasets that are obtainable during routine patient care.
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Affiliation(s)
- Josef A Vogt
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Ulm, Germany; and
| | - Christian Domzig
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Christian Denzer
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
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Bellanger S, Benrezzak O, Battista MC, Naimi F, Labbé SM, Frisch F, Normand-Lauzière F, Gallo-Payet N, Carpentier AC, Baillargeon JP. Experimental dog model for assessment of fasting and postprandial fatty acid metabolism: pitfalls and feasibility. Lab Anim 2015; 49:228-40. [PMID: 25563731 DOI: 10.1177/0023677214566021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dog is a widely-used model for conducting metabolic studies. This is mainly due to its large size and its physiology which is relatively similar to that of humans. Here, we attempted to optimize a postprandial metabolic study protocol used in dogs. Following acclimatization, female mongrel dogs underwent 9 h profiling for time-course baseline plasma data on triglyceride, adrenocorticotropic hormone (ACTH) and cortisol levels. One week later, carotid and jugular catheters were surgically inserted for sampling and infusions. Initial post-operative care, based on the literature (Protocol 1), consisted of analgesia (buprenorphine every 8-12 h and 2-3 doses/day of acepromazine), restriction by Pavlov harness within cages, and a two- to three-day recovery period. Throughout the experiment, dogs received a lipid tracer diluted in 5% bovine serum albumin (BSA). Compared with baseline, animals vomited (n = 6/6) and exhibited high ACTH + cortisol levels (stress biomarkers), resulting in blunted triglyceride peak levels. To avoid these undesirable effects, post-operative care was modified (Protocol 2) as follows: animals (n = 19) were given a single dose of buprenorphine and no acepromazine, were unrestrained and free to move within cages, the recovery period was extended to seven days, and the lipid tracer was diluted in 0.002% versus 5% BSA. Using this modified protocol, postprandial plasma-triglyceride and ACTH/cortisol patterns were similar to baseline values. Controlling for stressors, as well as for factors which may alter proper digestion, is critical for all postprandial metabolic studies. Our results show that an optimized postprandial metabolic protocol used in dogs reduces experimental variability, while improving animal care and comfort.
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Affiliation(s)
- S Bellanger
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - O Benrezzak
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - M C Battista
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - F Naimi
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - S M Labbé
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - F Frisch
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - F Normand-Lauzière
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - N Gallo-Payet
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - A C Carpentier
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - J P Baillargeon
- Division of Endocrinology, Department of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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11
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Hung CS, Lee JK, Yang CY, Hsieh HR, Ma WY, Lin MS, Liu PH, Shih SR, Liou JM, Chuang LM, Chen MF, Lin JW, Wei JN, Li HY. Measurement of visceral fat: should we include retroperitoneal fat? PLoS One 2014; 9:e112355. [PMID: 25401949 PMCID: PMC4234414 DOI: 10.1371/journal.pone.0112355] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/18/2014] [Indexed: 12/21/2022] Open
Abstract
Objective Whether retroperitoneal fat should be included in the measurement of visceral fat remains controversial. We compared the relationships of fat areas in peritoneal, retroperitoneal, and subcutaneous compartments to metabolic syndrome, adipokines, and incident hypertension and diabetes. Methods We enrolled 432 adult participants (153 men and 279 women) in a community-based cohort study. Computed tomography at the umbilicus level was used to measure the fat areas. Results Retroperitoneal fat correlated significantly with metabolic syndrome (adjusted odds ratio (OR), 5.651, p<0.05) and the number of metabolic abnormalities (p<0.05). Retroperitoneal fat area was significantly associated with blood pressure, plasma glycemic indices, lipid profile, C-reactive protein, adiponectin (r = −0.244, P<0.05), and leptin (r = 0.323, p<0.05), but not plasma renin or aldosterone concentrations. During the 2.94±0.84 years of follow-up, 32 participants developed incident hypertension. Retroperitoneal fat area (hazard ration (HR) 1.62, p = 0.003) and peritoneal fat area (HR 1.62, p = 0.009), but not subcutaneous fat area (p = 0.14) were associated with incident hypertension. Neither retroperitoneal fat area, peritoneal fat area, nor subcutaneous fat areas was associated with incident diabetes after adjustment. Conclusions Retroperitoneal fat is similar to peritoneal fat, but differs from subcutaneous fat, in terms of its relationship with metabolic syndrome and incident hypertension. Retroperitoneal fat area should be included in the measurement of visceral fat for cardio-metabolic studies in human.
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Affiliation(s)
- Chi-Sheng Hung
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jen-Kuang Lee
- Department of Clinical Pathology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Chung-Yi Yang
- Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hung-Ren Hsieh
- Department of Radiology, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan
| | - Wen-Ya Ma
- Division of Endocrinology, Department of Internal Medicine, Cardinal Tien Hospital, Xindian, Taiwan
| | - Mao-Shin Lin
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Pi-Hua Liu
- Clinical Informatics and Medical Statistics Research Center, Chang Gung University, Gueishan, Taiwan
| | - Shyang-Rong Shih
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jyh-Ming Liou
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Lee-Ming Chuang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ming-Fong Chen
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jou-Wei Lin
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan
| | - Jung-Nan Wei
- Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Hung-Yuan Li
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail:
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12
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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13
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Brandimarti P, Costa-Júnior JM, Ferreira SM, Protzek AO, Santos GJ, Carneiro EM, Boschero AC, Rezende LF. Cafeteria diet inhibits insulin clearance by reduced insulin-degrading enzyme expression and mRNA splicing. J Endocrinol 2013; 219:173-82. [PMID: 23959080 DOI: 10.1530/joe-13-0177] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Insulin clearance plays a major role in glucose homeostasis and insulin sensitivity in physiological and/or pathological conditions, such as obesity-induced type 2 diabetes as well as diet-induced obesity. The aim of the present work was to evaluate cafeteria diet-induced obesity-induced changes in insulin clearance and to explain the mechanisms underlying these possible changes. Female Swiss mice were fed either a standard chow diet (CTL) or a cafeteria diet (CAF) for 8 weeks, after which we performed glucose tolerance tests, insulin tolerance tests, insulin dynamics, and insulin clearance tests. We then isolated pancreatic islets for ex vivo glucose-stimulated insulin secretion as well as liver, gastrocnemius, visceral adipose tissue, and hypothalamus for subsequent protein analysis by western blot and determination of mRNA levels by real-time RT-PCR. The cafeteria diet induced insulin resistance, glucose intolerance, and increased insulin secretion and total insulin content. More importantly, mice that were fed a cafeteria diet demonstrated reduced insulin clearance and decay rate as well as reduced insulin-degrading enzyme (IDE) protein and mRNA levels in liver and skeletal muscle compared with the control animals. Furthermore, the cafeteria diet reduced IDE expression and alternative splicing in the liver and skeletal muscle of mice. In conclusion, a cafeteria diet impairs glucose homeostasis by reducing insulin sensitivity, but it also reduces insulin clearance by reducing IDE expression and alternative splicing in mouse liver; however, whether this mechanism contributes to the glucose intolerance or helps to ameliorate it remains unclear.
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Affiliation(s)
- P Brandimarti
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), PO Box 6109, Campinas, SP, CEP 13083-865, Brazil
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14
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Lee CC, Haffner SM, Wagenknecht LE, Lorenzo C, Norris JM, Bergman RN, Stefanovski D, Anderson AM, Rotter JI, Goodarzi MO, Hanley AJ. Insulin clearance and the incidence of type 2 diabetes in Hispanics and African Americans: the IRAS Family Study. Diabetes Care 2013; 36:901-7. [PMID: 23223351 PMCID: PMC3609510 DOI: 10.2337/dc12-1316] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE We aimed to identify factors that are independently associated with the metabolic clearance rate of insulin (MCRI) and to examine the association of MCRI with incident type 2 diabetes in nondiabetic Hispanics and African Americans. RESEARCH DESIGN AND METHODS We investigated 1,116 participants in the Insulin Resistance Atherosclerosis Study (IRAS) Family Study with baseline examinations from 2000 to 2002 and follow-up examinations from 2005 to 2006. Insulin sensitivity (S(I)), acute insulin response (AIR), and MCRI were determined at baseline from frequently sampled intravenous glucose tolerance tests. MCRI was calculated as the ratio of the insulin dose over the incremental area under the curve of insulin. Incident diabetes was defined as fasting glucose ≥126 mg/dL or antidiabetic medication use by self-report. RESULTS We observed that S(I) and HDL cholesterol were independent positive correlates of MCRI, whereas fasting insulin, fasting glucose, subcutaneous adipose tissue, visceral adipose tissue, and AIR were independent negative correlates (all P < 0.05) at baseline. After 5 years of follow-up, 71 (6.4%) participants developed type 2 diabetes. Lower MCRI was associated with a higher risk of incident diabetes after adjusting for demographics, lifestyle factors, HDL cholesterol, indexes of obesity and adiposity, and insulin secretion (odds ratio 2.01 [95% CI 1.30-3.10], P = 0.0064, per one-SD decrease in loge-transformed MCRI). CONCLUSIONS Our data showed that lower MCRI predicts the incidence of type 2 diabetes.
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Affiliation(s)
- C Christine Lee
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
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15
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Rezende LF, Santos GJ, Santos-Silva JC, Carneiro EM, Boschero AC. Ciliary neurotrophic factor (CNTF) protects non-obese Swiss mice against type 2 diabetes by increasing beta cell mass and reducing insulin clearance. Diabetologia 2012; 55:1495-504. [PMID: 22349107 DOI: 10.1007/s00125-012-2493-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 01/19/2012] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Ciliary neurotrophic factor (CNTF) improves metabolic variables of obese animals with characteristics of type 2 diabetes, mainly by reducing insulin resistance. We evaluated whether CNTF was able to improve other metabolic variables in mouse models of type 2 diabetes, such as beta cell mass and insulin clearance, and whether CNTF has any effect on non-obese mice with characteristics of type 2 diabetes. METHODS Neonatal mice were treated with 0.1 mg/kg CNTF or citrate buffer via intraperitoneal injections, before injection of 250 mg/kg alloxan. HEPG2 cells were cultured for 3 days in the presence of citrate buffer, 1 nmol/l CNTF or 50 mmol/l alloxan or a combination of CNTF and alloxan. Twenty-one days after treatment, we determined body weight, epididymal fat weight, blood glucose, plasma insulin, NEFA, glucose tolerance, insulin resistance, insulin clearance and beta cell mass. Finally, we assessed insulin receptor and protein kinase B phosphorylation in peripheral organs, as well as insulin-degrading enzyme (IDE) protein production and alternative splicing in the liver and HEPG2 cells. RESULTS CNTF improved insulin sensitivity and beta cell mass, while reducing glucose-stimulated insulin secretion and insulin clearance in Swiss mice, improving glucose handling in a non-obese type 2 diabetes model. This effect was associated with lower IDE production and activity in liver cells. All these effects were observed even at 21 days after CNTF treatment. CONCLUSIONS/INTERPRETATION CNTF protection against type 2 diabetes is partially independent of the anti-obesity actions of CNTF, requiring a reduction in insulin clearance and increased beta cell mass, besides increased insulin sensitivity. Furthermore, knowledge of the long-term effects of CNTF expands its pharmacological relevance.
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Affiliation(s)
- L F Rezende
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, PO Box 6109, Campinas, SP CEP 13083-865, Brazil.
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Jensen MD, Nielsen S, Gupta N, Basu R, Rizza RA. Insulin clearance is different in men and women. Metabolism 2012; 61:525-30. [PMID: 22000585 PMCID: PMC3274596 DOI: 10.1016/j.metabol.2011.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 08/22/2011] [Accepted: 08/23/2011] [Indexed: 11/29/2022]
Abstract
Insulin is often infused based upon total body weight (TBW) or fat-free mass (FFM) for glucose clamp protocols. We observed greater insulin concentrations in men than women using this approach and examined whether splanchnic insulin extraction accounts for the differences. Whole-body insulin clearance was measured during a pancreatic clamp study (somatostatin to inhibit islet hormone secretion) including 13 adults (6 men); and whole-body insulin clearance was measured during a euglycemic, hyperinsulinemic clamp study including 27 adults (13 men). Femoral artery and hepatic vein blood samples were collected to measure splanchnic insulin balance. For the pancreatic clamp study, insulin was infused at rates of 0.5, 1.0, and 2.0 mU/kg of TBW per minute; and for the euglycemic, hyperinsulinemic clamp study, insulin was infused at 2.5 mU/kg of FFM per minute. Significantly greater arterial insulin concentrations were found in men than women. Splanchnic plasma flow was similar in men and women in both protocols. Splanchnic insulin extraction and the fraction of infused insulin removed by splanchnic bed were significantly greater in men than in women. However, whole-body insulin clearance was greater in women than men. Infusing insulin per body weight or FFM results in higher plasma insulin concentrations in men than women. Splanchnic insulin extraction is greater in men, indicating that greater peripheral insulin clearance in women accounts for the sex differences we observed. This finding has implications for insulin clamp study design and raises the question of which tissues take up more insulin in women.
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17
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ER Stress and Lipid Metabolism in Adipocytes. Biochem Res Int 2012; 2012:312943. [PMID: 22400114 PMCID: PMC3287011 DOI: 10.1155/2012/312943] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 10/28/2011] [Indexed: 12/29/2022] Open
Abstract
The role of endoplasmic reticulum (ER) stress is a rapidly emerging field of interest in the pathogenesis of metabolic diseases. Recent studies have shown that chronic activation of ER stress is closely linked to dysregulation of lipid metabolism in several metabolically important cells including hepatocytes, macrophages, β-cells, and adipocytes. Adipocytes are one of the major cell types involved in the pathogenesis of the metabolic syndrome. Recent advances in dissecting the cellular and molecular mechanisms involved in the regulation of adipogenesis and lipid metabolism indicate that activation of ER stress plays a central role in regulating adipocyte function. In this paper, we discuss the current understanding of the potential role of ER stress in lipid metabolism in adipocytes. In addition, we touch upon the interaction of ER stress and autophagy as well as inflammation. Inhibition of ER stress has the potential of decreasing the pathology in adipose tissue that is seen with energy overbalance.
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Spruijt-Metz D. Etiology, Treatment and Prevention of Obesity in Childhood and Adolescence: A Decade in Review. JOURNAL OF RESEARCH ON ADOLESCENCE : THE OFFICIAL JOURNAL OF THE SOCIETY FOR RESEARCH ON ADOLESCENCE 2011; 21:129-152. [PMID: 21625328 PMCID: PMC3102537 DOI: 10.1111/j.1532-7795.2010.00719.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Childhood obesity has become an epidemic on a worldwide scale. This article gives an overview of the progress made in childhood and adolescent obesity research in the last decade, with a particular emphasis on the transdisciplinary and complex nature of the problem. The following topics are addressed: 1) current definitions of childhood and adolescent overweight and obesity; 2) demography of childhood and adolescent obesity both in the US and globally; 3) current topics in the physiology of fat and obesity; 4) psychosocial correlates of childhood and adolescent overweight and obesity; 5) the three major obesity-related behaviors, i.e. dietary intake, physical activity and sleep; 6) genes components of childhood and adolescent obesity; 7) environment and childhood and adolescent obesity; and 8) progress in interventions to prevent and treat childhood obesity. The article concludes with recommendations for future research, including the need for large-scale, high dose and long-term interventions that take into account the complex nature of the problem.
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Affiliation(s)
- Donna Spruijt-Metz
- Keck School of Medicine, University of Southern California, 1000 S. Fremont, Unit 8, room 4101, Alhambra, CA 91803, 626 4576631, fax: 626 4576633,
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de las Fuentes L, de Simone G, Arnett DK, Dávila-Román VG. Molecular determinants of the cardiometabolic phenotype. Endocr Metab Immune Disord Drug Targets 2011; 10:109-23. [PMID: 20384572 DOI: 10.2174/187153010791213119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 04/04/2010] [Indexed: 12/25/2022]
Abstract
The metabolic syndrome represents a clustering of risk factors that has been shown to predict adverse cardiovascular outcomes. Although the precise mechanisms contributing to the cardiometabolic syndrome (CMS) remain poorly defined, accumulating evidence identifies two intersecting candidate pathways responsible for inflammation and energy homeostasis in the pathophysiology that underlie cardiometabolic traits. Although currently no pharmacologic interventions specifically target CMS, future drug development efforts should attempt to capitalize on molecular nodes at the intersections of these pathways in the CMS.
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Affiliation(s)
- Lisa de las Fuentes
- Cardiovascular Imaging and Clinical Research Core Laboratory, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO 63110, USA.
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20
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Vranic M. Odyssey between Scylla and Charybdis through storms of carbohydrate metabolism and diabetes: a career retrospective. Am J Physiol Endocrinol Metab 2010; 299:E849-67. [PMID: 20823450 DOI: 10.1152/ajpendo.00344.2010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This research perspective allows me to summarize some of my work completed over 50 years, and it is organized in seven sections. 1) The treatment of diabetes concentrates on the liver and/or the periphery. We quantified hormonal and metabolic interactions involved in physiology and the pathogenesis of diabetes by developing tracer methods to separate the effects of diabetes on both. We collaborated in the first tracer clinical studies on insulin resistance, hypertriglyceridemia, and the Cori cycle. 2) Diabetes reflects insulin deficiency and glucagon abundance. Extrapancreatic glucagon changed the prevailing dogma and permitted precise exploration of the roles of insulin and glucagon in physiology and diabetes. 3) We established the critical role of glucagon-insulin interaction and the control of glucose metabolism during moderate exercise and of catecholamines during strenuous exercise. Deficiencies of the release and effects of these hormones were quantified in diabetes. We also revealed how acute and chronic hyperglycemia affects the expression of GLUT2 gene and protein in diabetes. 4) We outlined molecular and physiological mechanisms whereby exercise training and repetitive neurogenic stress can prevent diabetes in ZDF rats. 5) We and others established that the indirect effect of insulin plays an important role in the regulation of glucose production in dogs. We confirmed this effect in humans and demonstrated that in type 2 diabetes it is mainly the indirect effect. 6) We indicated that the muscle and the liver protected against glucose changes. 7) We described molecular mechanisms responsible for increased HPA axis in diabetes and for the diminished responses of HPA axis, catecholamines, and glucagon to hypoglycemia. We proposed a new approach to decrease the threat of hypoglycemia.
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Affiliation(s)
- Mladen Vranic
- Dept. of Physiology, Univ. of Toronto, Toronto, ON. Canada M5S 1A8.
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Lu Y, Han P, Zhao S, Zhang YY, He B, Zhang W. Effects of free fatty acid elevation on hepatic insulin resistance and hepatic oxidative stress. Shijie Huaren Xiaohua Zazhi 2009; 17:2405-2408. [DOI: 10.11569/wcjd.v17.i23.2405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effects of long-term elevation of free fatty acids (FFA) on hepatic insulin resistance and hepatic oxidative stress.
METHODS: A total of 32 Wistar rats were divided into two groups and given an intravenous infusion of intralipid plus heparin (IH) and saline (SAL), respectively. Two hours before the end of the infusion, a hyperinsulinemic-euglycemic clamp was performed to examine the ability of FFA to induce hepatic insulin resistance. After the clamp, liver tissue samples were taken to determine the protein carbonyl content by DNPH (2,4-dinitrophenylhydrazine) colorimetry and the content of protein kinase C-δ by Western blot.
RESULTS: Compared to SAL infusion, IH infusion resulted in an increase in plasma FFA level by 4.3 folds (P < 0.001), hepatic protein carbonyl content by 3.2 folds, and the membrane/cytosol ratio of PKC-δ by 4.0 folds (P < 0.001).
CONCLUSION: Long-term elevation of FFA induces elevation of hepatic protein carbonyl content, PKC-δ translocation and insulin resistance, suggesting that PKC-δ plays an important role in FFA-induced hepatic insulin resistance.
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Viljanen APM, Iozzo P, Borra R, Kankaanpää M, Karmi A, Lautamäki R, Järvisalo M, Parkkola R, Rönnemaa T, Guiducci L, Lehtimäki T, Raitakari OT, Mari A, Nuutila P. Effect of weight loss on liver free fatty acid uptake and hepatic insulin resistance. J Clin Endocrinol Metab 2009; 94:50-5. [PMID: 18957499 DOI: 10.1210/jc.2008-1689] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Weight loss has been shown to decrease liver fat content and whole-body insulin resistance. The current study was conducted to investigate the simultaneous effects of rapid weight reduction with a very-low-calorie diet on liver glucose and fatty acid metabolism and liver adiposity. HYPOTHESIS We hypothesized that liver insulin resistance and free fatty acid uptake would decrease after weight loss and that they are associated with reduction of liver fat content. DESIGN Thirty-four healthy obese subjects (body mass index, 33.7 +/- 8.0 kg/m(2)) were studied before and after a very-low-calorie diet for 6 wk. Hepatic glucose uptake and endogenous glucose production were measured with [(18)F]fluorodeoxyglucose during hyperinsulinemic euglycemia and fasting hepatic fatty acid uptake with [(18)F]fluoro-6-thia-heptadecanoic acid and positron emission tomography. Liver volume and fat content were measured using magnetic resonance imaging and spectroscopy. RESULTS Subjects lost weight (11.2 +/- 2.9 kg; P < 0.0001). Liver volume decreased by 11% (P < 0.002), which was partly explained by decreased liver fat content (P < 0.0001). Liver free fatty acid uptake was 26% lower after weight loss (P < 0.003) and correlated with the decrement in liver fat content (r = 0.54; P < 0.03). Hepatic glucose uptake during insulin stimulation was unchanged, but the endogenous glucose production decreased by 40% (P < 0.04), and hepatic insulin resistance by 40% (P < 0.05). CONCLUSIONS The liver responds to a 6-wk period of calorie restriction with a parallel reduction in lipid uptake and storage, accompanied by enhancement of hepatic insulin sensitivity and clearance.
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Affiliation(s)
- Antti P M Viljanen
- Turku PET Centre, Turku University Hospital, P.O. Box 52, FIN-20521, Turku, Finland
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Mittra S, Bansal VS, Bhatnagar PK. From a glucocentric to a lipocentric approach towards metabolic syndrome. Drug Discov Today 2008; 13:211-8. [DOI: 10.1016/j.drudis.2008.01.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 12/13/2007] [Accepted: 01/15/2008] [Indexed: 12/14/2022]
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Abstract
OBJECTIVES Early hyperglycemia in acute pancreatitis (AP) is a prognostic sign of severe attack. Obesity, another risk factor for severe AP, is associated with impaired glucose regulation. We hypothesized that obesity is related to early hyperglycemia in patients with severe AP. METHODS Forty-four patients with severe AP with organ failure and 127 control patients with AP (33 severe AP and 94 mild AP) but without organ failure were studied. Plasma glucose and patients' height and weight for calculation of body mass index (BMI) were measured at admission. RESULTS Body mass index was higher in organ failure patients than in controls (median, 27.0 kg/m2 [interquartile range, 24.9-30.4 kg/m2] vs 25.2 kg/m2 [interquartile range, 23.3-27.9 kg/m2; P = 0.007). Glucose level correlated with BMI in organ failure patients (r = 0.463, P = 0.002) but not in controls (r = 0.096, P = 0.28). Eight (18%) organ failure patients and 7 (5.5%) controls had prior type 2 diabetes (P = 0.025). In a logistic regression model, admission glucose level was the only independent predictor of organ failure. CONCLUSIONS Obesity may contribute to early hyperglycemia in patients with AP. Multivariate analysis indicated that obesity is not an independent risk factor for organ failure, but it correlates with early hyperglycemia, which may predispose to systemic complications in AP.
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Hsu IR, Kim SP, Kabir M, Bergman RN. Metabolic syndrome, hyperinsulinemia, and cancer. Am J Clin Nutr 2007; 86:s867-71. [PMID: 18265480 DOI: 10.1093/ajcn/86.3.867s] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The term metabolic syndrome describes the association between obesity, insulin resistance, and the risk of several prominent chronic diseases, including cancer. The causal link between many of these components remains unexplained, however. What is clear are the events that precede the development of the syndrome itself. In animal models, a fat-supplemented diet causes 1) lipid deposition in adipose depots, 2) insulin resistance of liver and skeletal muscle, and 3) hyperinsulinemia. One hypothesis relating fat deposition and insulin resistance involves enhanced lipolysis in the visceral depot, which leads to an increase in free fatty acid (FFA) flux. Increased mass of stored lipid and insulin resistance of visceral adipocytes favors lipolysis. Additionally, hypersensitivity of visceral adipose cells to sympathetic nervous system stimulation leads to increased lipolysis in the obese state. However, little evidence is available for enhanced plasma FFA concentrations in the fasting state. We measured FFA concentrations over a 24-h day in obese animals and found that plasma FFAs are elevated in the middle of the night, peaking at 0300. Therefore, it is possible that nocturnal lipolysis increases exposure of liver and muscle to FFAs at night, thus causing insulin resistance, which may play a role in hyperinsulinemic compensation to insulin resistance. Nocturnal lipolysis secondary to sympathetic stimulation may not only cause insulin resistance but also be responsible for hyperinsulinemia by stimulating secretion and reducing clearance of insulin by the liver. The resulting syndrome-elevated nocturnal FFAs and elevated insulin-may synergize and increase the risk of some cancers. This possible scenario needs further study.
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Affiliation(s)
- Isabel R Hsu
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA 90033, USA
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2007; 14:329-57. [PMID: 17940461 DOI: 10.1097/med.0b013e3282c3a898] [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] [Indexed: 11/25/2022]
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