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Miller C, Pachanski MJ, Kirkland ME, Kosinski DT, Mane J, Bunzel M, Cao J, Souza S, Thomas-Fowlkes B, Di Salvo J, Weinglass AB, Li X, Myers RW, Knagge K, Carrington PE, Hagmann WK, Trujillo ME. GPR40 partial agonist MK-2305 lower fasting glucose in the Goto Kakizaki rat via suppression of endogenous glucose production. PLoS One 2017; 12:e0176182. [PMID: 28542610 PMCID: PMC5441580 DOI: 10.1371/journal.pone.0176182] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/06/2017] [Indexed: 11/19/2022] Open
Abstract
GPR40 (FFA1) is a fatty acid receptor whose activation results in potent glucose lowering and insulinotropic effects in vivo. Several reports illustrate that GPR40 agonists exert glucose lowering in diabetic humans. To assess the mechanisms by which GPR40 partial agonists improve glucose homeostasis, we evaluated the effects of MK-2305, a potent and selective partial GPR40 agonist, in diabetic Goto Kakizaki rats. MK-2305 decreased fasting glucose after acute and chronic treatment. MK-2305-mediated changes in glucose were coupled with increases in plasma insulin during hyperglycemia and glucose challenges but not during fasting, when glucose was normalized. To determine the mechanism(s) mediating these changes in glucose metabolism, we measured the absolute contribution of precursors to glucose production in the presence or absence of MK-2305. MK-2305 treatment resulted in decreased endogenous glucose production (EGP) driven primarily through changes in gluconeogenesis from substrates entering at the TCA cycle. The decrease in EGP was not likely due to a direct effect on the liver, as isolated perfused liver studies showed no effect of MK-2305 ex vivo and GPR40 is not expressed in the liver. Taken together, our results suggest MK-2305 treatment increases glucose stimulated insulin secretion (GSIS), resulting in changes to hepatic substrate handling that improve glucose homeostasis in the diabetic state. Importantly, these data extend our understanding of the underlying mechanisms by which GPR40 partial agonists reduce hyperglycemia.
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Affiliation(s)
- Corin Miller
- Departments of Translational Imaging Biomarkers, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Michele J. Pachanski
- In Vivo Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Melissa E. Kirkland
- In Vivo Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Daniel T. Kosinski
- In Vivo Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Joel Mane
- In Vivo Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Michelle Bunzel
- Departments of Translational Imaging Biomarkers, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Jin Cao
- Departments of Translational Imaging Biomarkers, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Sarah Souza
- In Vitro Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Brande Thomas-Fowlkes
- In Vitro Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Jerry Di Salvo
- In Vitro Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Adam B. Weinglass
- In Vitro Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Xiaoyan Li
- Cardio-Metabolic Diseases, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Robert W. Myers
- In Vitro Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Kevin Knagge
- David H Murdock Research Institute, Kannapolis, North Carolina, United States of America
| | - Paul E. Carrington
- Cardio-Metabolic Diseases, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - William K. Hagmann
- Chemistry, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Maria E. Trujillo
- In Vivo Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
- * E-mail:
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152
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Kim DJ, Kang YH, Kim KK, Kim TW, Park JB, Choe M. Increased glucose metabolism and alpha-glucosidase inhibition in Cordyceps militaris water extract-treated HepG2 cells. Nutr Res Pract 2017; 11:180-189. [PMID: 28584574 PMCID: PMC5449374 DOI: 10.4162/nrp.2017.11.3.180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 12/29/2016] [Accepted: 04/02/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND/OBJECTIVES Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism. MATERIALS/METHODS Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha (HNF-1α), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta (GSK-3β) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement. RESULTS CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through HNF-1α expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and GSK-3β, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of α-glucosidase inhibitory activity than that from acarbose. CONCLUSION CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment.
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Affiliation(s)
- Dae Jung Kim
- Well-being Bioproducts RIC, Kangwon National University, Gangwon 25209, Korea
| | - Yun Hwan Kang
- National Development Institute of Korean Medicine, Gyeongbuk 38540, Korea
| | - Kyoung Kon Kim
- Department of Bio-Health Technology, Kangwon National University, 1 Gangwondaehak-gil, Chuncheon, Gangwon 24341, Korea
| | - Tae Woo Kim
- Well-being Bioproducts RIC, Kangwon National University, Gangwon 25209, Korea
| | - Jae Bong Park
- Department of Biochemistry, Hallym University College of Medicine, Gangwon 24252, Korea
| | - Myeon Choe
- Well-being Bioproducts RIC, Kangwon National University, Gangwon 25209, Korea.,Department of Bio-Health Technology, Kangwon National University, 1 Gangwondaehak-gil, Chuncheon, Gangwon 24341, Korea
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153
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Dion F, Dumayne C, Henley N, Beauchemin S, Arias EB, Leblond FA, Lesage S, Lefrançois S, Cartee GD, Pichette V. Mechanism of insulin resistance in a rat model of kidney disease and the risk of developing type 2 diabetes. PLoS One 2017; 12:e0176650. [PMID: 28459862 PMCID: PMC5411038 DOI: 10.1371/journal.pone.0176650] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/13/2017] [Indexed: 12/19/2022] Open
Abstract
Chronic kidney disease is associated with homeostatic imbalances such as insulin resistance. However, the underlying mechanisms leading to these imbalances and whether they promote the development of type 2 diabetes is unknown. The effect of chronic kidney disease on insulin resistance was studied on two different rat strains. First, in a 5/6th nephrectomised Sprague-Dawley rat model of chronic kidney disease, we observed a correlation between the severity of chronic kidney disease and hyperglycemia as evaluated by serum fructosamine levels (p<0.0001). Further, glucose tolerance tests indicated an increase of 25% in glycemia in chronic kidney disease rats (p<0.0001) as compared to controls whereas insulin levels remained unchanged. We also observed modulation of glucose transporters expression in several tissues such as the liver (decrease of ≈40%, p≤0.01) and muscles (decrease of ≈29%, p≤0.05). Despite a significant reduction of ≈37% in insulin-dependent glucose uptake in the muscles of chronic kidney disease rats (p<0.0001), the development of type 2 diabetes was never observed. Second, in a rat model of metabolic syndrome (Zucker Leprfa/fa), chronic kidney disease caused a 50% increased fasting hyperglycemia (p<0.0001) and an exacerbated glycemic response (p<0.0001) during glucose challenge. Similar modulations of glucose transporters expression and glucose uptake were observed in the two models. However, 30% (p<0.05) of chronic kidney disease Zucker rats developed characteristics of type 2 diabetes. Thus, our results suggest that downregulation of GLUT4 in skeletal muscle may be associated with insulin resistance in chronic kidney disease and could lead to type 2 diabetes in predisposed animals.
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Affiliation(s)
- François Dion
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (VP); (FD)
| | - Christopher Dumayne
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Nathalie Henley
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Stéphanie Beauchemin
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Edward B. Arias
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - François A. Leblond
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
| | - Sylvie Lesage
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de microbiologie, infectiologie et immunologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Stéphane Lefrançois
- Centre INRS-Institut Armand-Frappier, Institut National de la Recherche Scientifique, Laval, Québec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Gregory D. Cartee
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Vincent Pichette
- Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Faculté de Médecine, Centre affilié à l’Université de Montréal, Montréal, Québec, Canada
- Département de pharmacologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (VP); (FD)
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154
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Yuan J, Wang X, Yin D, Wang M, Yin X, Lei Z, Guo Y. Effect of different amylases on the utilization of cornstarch in broiler chickens. Poult Sci 2017; 96:1139-1148. [DOI: 10.3382/ps/pew323] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/05/2016] [Indexed: 01/09/2023] Open
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155
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Yang G, Qin C, Wang B, Jia J, Yuan X, Sun C, Li W. Molecular identification and functional analysis of Ctrp9 in Epinephelus coioides. J Mol Endocrinol 2017; 58:179-191. [PMID: 28283578 DOI: 10.1530/jme-16-0171] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/10/2017] [Indexed: 01/06/2023]
Abstract
CTRP9 is a member of the C1q/TNF-related protein (CTRP) superfamily and has been studied in mammals, whereas the comparative studies of CTRP9 in non-mammalian species are still absent. In this study, ctrp9 was isolated and characterized from the orange-spotted grouper (Epinephelus coioides). The full-length cDNA of ctrp9 was 1378 bp in size with an ORF (open reading frame) of 1020 bp that encodes a 339 amino acid pre-pro hormone. The mRNA expression of ctrp9 showed a rather high level in the kidney and brain, but a low level in other tissues. Furthermore, the mRNA expression of ctrp9 decreased significantly in the liver after fasting for 7 days and restored to the normal levels after refeeding. In contrast, the ctrp9 mRNA level increased in the hypothalamus after fasting. The recombinant gCtrp9 (globular Ctrp9) was prepared using the Pichia pastoris expression system and was verified by Western blot as well as mass spectrometry assays. In the primary hepatocytes culture, the recombinant gCtrp9 could inhibit the glucose production after 12-h treatment. After i.p. (intraperitoneal) injection with recombinant gCtrp9, in hypothalamus, mRNA expression levels of npy and orexin (orexigenic factors) decreased, whereas the expression levels of crh and pomc (anorexigenic factors) increased. Moreover, i.p. injection with the recombinant gCtrp9 could reduce the serum concentrations of glucose, TG and low-density lipoprotein cholesterol but increase the content of high-density lipoprotein cholesterol. Our studies for the first time unveil the structure of Ctrp9 and its potential role as a regulatory factor of metabolism and food intake in teleost.
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Affiliation(s)
- Guokun Yang
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Chaobin Qin
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Bin Wang
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Jirong Jia
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xi Yuan
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Caiyun Sun
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Wensheng Li
- State Key Laboratory of BiocontrolInstitute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
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156
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Moore MC, Smith MS, Farmer B, Kraft G, Shiota M, Williams PE, Cherrington AD. Priming Effect of a Morning Meal on Hepatic Glucose Disposition Later in the Day. Diabetes 2017; 66:1136-1145. [PMID: 28174290 PMCID: PMC5399607 DOI: 10.2337/db16-1308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/28/2017] [Indexed: 01/15/2023]
Abstract
We used hepatic balance and tracer ([3H]glucose) techniques to examine the impact of "breakfast" on hepatic glucose metabolism later in the same day. From 0-240 min, 2 groups of conscious dogs (n = 9 dogs/group) received a duodenal infusion of glucose (GLC) or saline (SAL), then were fasted from 240-360 min. Three dogs from each group were euthanized and tissue collected at 360 min. From 360-600 min, the remaining dogs underwent a hyperinsulinemic (4× basal) hyperglycemic clamp (arterial blood glucose 146 ± 2 mg/dL) with portal GLC infusion. The total GLC infusion rate was 14% greater in dogs infused with GLC than in those receiving SAL (AUC360-600min 2,979 ± 296 vs. 2,597 ± 277 mg/kg, respectively). The rates of hepatic glucose uptake (5.8 ± 0.8 vs. 3.2 ± 0.3 mg ⋅ kg-1 ⋅ min-1) and glycogen storage (4.7 ± 0.6 vs. 2.9 ± 0.3 mg ⋅ kg-1 ⋅ min-1) during the clamp were markedly greater in dogs receiving GLC compared with those receiving SAL. Hepatic glycogen content was ∼50% greater, glycogen synthase activity was ∼50% greater, glycogen phosphorylase activity was ∼50% lower, and the amount of phosphorylated glycogen synthase was 34% lower, indicating activation of the enzyme, in dogs receiving GLC compared with those receiving SAL. Thus, morning GLC primed the liver to extract and store more glucose in the presence of hyperinsulinemic hyperglycemia later in the same day, indicating that breakfast enhances the liver's role in glucose disposal in subsequent same-day meals.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Marta S Smith
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Ben Farmer
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Guillaume Kraft
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Masakazu Shiota
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Phillip E Williams
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN
| | - Alan D Cherrington
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
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157
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Rosset R, Egli L, Lecoultre V. Glucose-fructose ingestion and exercise performance: The gastrointestinal tract and beyond. Eur J Sport Sci 2017; 17:874-884. [PMID: 28441908 DOI: 10.1080/17461391.2017.1317035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Carbohydrate ingestion can improve endurance exercise performance. In the past two decades, research has repeatedly reported the performance benefits of formulations comprising both glucose and fructose (GLUFRU) over those based on glucose (GLU). This has been usually related to additive effects of these two monosaccharides on the gastrointestinal tract whereby intestinal carbohydrate absorption is enhanced and discomfort limited. This is only a partial explanation, since glucose and fructose are also metabolized through different pathways after being absorbed from the gut. In contrast to glucose that is readily used by every body cell type, fructose is specifically targeted to the liver where it is mainly converted into glucose and lactate. The ingestion of GLUFRU may thereby profoundly alter hepatic function ultimately raising both glucose and lactate fluxes. During exercise, this particular profile of circulating carbohydrate may induce a spectrum of effects on muscle metabolism possibly resulting in an improved performance. Compared to GLU alone, GLUFRU ingestion could also induce several non-metabolic effects which are so far largely unexplored. Through its metabolite lactate, fructose may act on central fatigue and/or alter metabolic regulation. Future research could further define the effects of GLUFRU over other exercise modalities and different athletic populations, using several of the hypotheses discussed in this review.
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Affiliation(s)
- Robin Rosset
- a Department of Physiology , University of Lausanne , Lausanne , Switzerland
| | - Léonie Egli
- b Nestle Research Center Singapore , Singapore , Singapore
| | - Virgile Lecoultre
- c Centre for Metabolic Disease , Broye Intercantonal Hospital , Estavayer-le-Lac , Switzerland
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158
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Weis J, Kullberg J, Ahlström H. Multiple breath-hold proton spectroscopy of human liver at 3T: Relaxation times and concentrations of glycogen, choline, and lipids. J Magn Reson Imaging 2017; 47:410-417. [PMID: 28419608 DOI: 10.1002/jmri.25734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/29/2017] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To evaluate the feasibility of an expiration multiple breath-hold 1 H-MRS technique to measure glycogen (Glycg), choline-containing compounds (CCC), and lipid relaxation times T1 , T2 , and their concentrations in normal human liver. MATERIALS AND METHODS Thirty healthy volunteers were recruited. Experiments were performed at 3T. Multiple expiration breath-hold single-voxel point-resolved spectroscopy (PRESS) technique was used for localization. Water-suppressed spectra were used for the estimation of Glycg, CCC, lipid methylene (CH2 )n relaxation times and concentrations. Residual water lines were removed by the Hankel Lanczos singular value decomposition filter. After phase correction and frequency alignment, spectra were averaged and processed by LCModel. Summed signals of Glycg resonances H2H4', H3, and H5 between 3.6 and 4 ppm were used to estimate their apparent relaxation times and concentration. Glycg, CCC, and lipid content were estimated from relaxation corrected spectral intensity ratios to unsuppressed water line. RESULTS Relaxation times were measured for liver Glycg (T1 , 892 ± 126 msec; T2 , 13 ± 4 msec), CCC (T1 , 842 ± 75 msec; T2 , 50 ± 5 msec), lipid (CH2 )n (T1 , 402 ± 19 msec; T2 , 52 ± 3 msec), and water (T1 , 990 ± 89 msec; T2 , 30 ± 2 msec). Mean CCC and lipid concentrations of healthy liver were 7.8 ± 1.3 mM and 15.8 ± 23.6 mM, respectively. Glycg content was found lower in the morning (48 ± 21 mM) compared to the afternoon (145 ± 50 mM). CONCLUSION Multiple breath-hold 1 H-MRS together with dedicated postprocessing is a feasible technique for the quantification of liver Glycg, CCC, and lipid relaxation times and concentrations. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:410-417.
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Affiliation(s)
- Jan Weis
- Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden.,Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
| | - Joel Kullberg
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
| | - Håkan Ahlström
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
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159
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Song JJ, Wang Q, Du M, Chen B, Mao XY. Peptide IPPKKNQDKTE ameliorates insulin resistance in HepG2 cells via blocking ROS-mediated MAPK signaling. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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160
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de Souza CO, Teixeira AA, Biondo LA, Lima Junior EA, Batatinha HA, Rosa Neto JC. Palmitoleic Acid Improves Metabolic Functions in Fatty Liver by PPARα-Dependent AMPK Activation. J Cell Physiol 2017; 232:2168-2177. [DOI: 10.1002/jcp.25715] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/30/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Camila O. de Souza
- Department of Cell and Developmental Biology; University of São Paulo; São Paulo Brazil
| | | | - Luana A. Biondo
- Department of Cell and Developmental Biology; University of São Paulo; São Paulo Brazil
| | - Edson A. Lima Junior
- Department of Cell and Developmental Biology; University of São Paulo; São Paulo Brazil
| | - Helena A.P. Batatinha
- Department of Cell and Developmental Biology; University of São Paulo; São Paulo Brazil
| | - Jose C. Rosa Neto
- Department of Cell and Developmental Biology; University of São Paulo; São Paulo Brazil
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161
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Edgerton DS, Kraft G, Smith M, Farmer B, Williams PE, Coate KC, Printz RL, O'Brien RM, Cherrington AD. Insulin's direct hepatic effect explains the inhibition of glucose production caused by insulin secretion. JCI Insight 2017; 2:e91863. [PMID: 28352665 DOI: 10.1172/jci.insight.91863] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Insulin can inhibit hepatic glucose production (HGP) by acting directly on the liver as well as indirectly through effects on adipose tissue, pancreas, and brain. While insulin's indirect effects are indisputable, their physiologic role in the suppression of HGP seen in response to increased insulin secretion is not clear. Likewise, the mechanisms by which insulin suppresses lipolysis and pancreatic α cell secretion under physiologic circumstances are also debated. In this study, insulin was infused into the hepatic portal vein to mimic increased insulin secretion, and insulin's indirect liver effects were blocked either individually or collectively. During physiologic hyperinsulinemia, plasma free fatty acid (FFA) and glucagon levels were clamped at basal values and brain insulin action was blocked, but insulin's direct effects on the liver were left intact. Insulin was equally effective at suppressing HGP when its indirect effects were absent as when they were present. In addition, the inhibition of lipolysis, as well as glucagon and insulin secretion, did not require CNS insulin action or decreased plasma FFA. This indicates that the rapid suppression of HGP is attributable to insulin's direct effect on the liver and that its indirect effects are redundant in the context of a physiologic increase in insulin secretion.
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Affiliation(s)
- Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Phillip E Williams
- Division of Surgical Research, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Katie C Coate
- Samford University, Department of Nutrition and Dietetics, Birmingham, Alabama, USA
| | - Richard L Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Richard M O'Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
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162
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Sharabi K, Lin H, Tavares CDJ, Dominy JE, Camporez JP, Perry RJ, Schilling R, Rines AK, Lee J, Hickey M, Bennion M, Palmer M, Nag PP, Bittker JA, Perez J, Jedrychowski MP, Ozcan U, Gygi SP, Kamenecka TM, Shulman GI, Schreiber SL, Griffin PR, Puigserver P. Selective Chemical Inhibition of PGC-1α Gluconeogenic Activity Ameliorates Type 2 Diabetes. Cell 2017; 169:148-160.e15. [PMID: 28340340 PMCID: PMC5398763 DOI: 10.1016/j.cell.2017.03.001] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 12/22/2016] [Accepted: 02/27/2017] [Indexed: 01/27/2023]
Abstract
Type 2 diabetes (T2D) is a worldwide epidemic with a medical need for additional targeted therapies. Suppression of hepatic glucose production (HGP) effectively ameliorates diabetes and can be exploited for its treatment. We hypothesized that targeting PGC-1α acetylation in the liver, a chemical modification known to inhibit hepatic gluconeogenesis, could be potentially used for treatment of T2D. Thus, we designed a high-throughput chemical screen platform to quantify PGC-1α acetylation in cells and identified small molecules that increase PGC-1α acetylation, suppress gluconeogenic gene expression, and reduce glucose production in hepatocytes. On the basis of potency and bioavailability, we selected a small molecule, SR-18292, that reduces blood glucose, strongly increases hepatic insulin sensitivity, and improves glucose homeostasis in dietary and genetic mouse models of T2D. These studies have important implications for understanding the regulatory mechanisms of glucose metabolism and treatment of T2D.
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Affiliation(s)
- Kfir Sharabi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hua Lin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Clint D J Tavares
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - John E Dominy
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Joao Paulo Camporez
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Rachel J Perry
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Roger Schilling
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Amy K Rines
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jaemin Lee
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02130, USA
| | - Marc Hickey
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Melissa Bennion
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Michelle Palmer
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Partha P Nag
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - José Perez
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Umut Ozcan
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02130, USA
| | - Steve P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Theodore M Kamenecka
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | | | - Patrick R Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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163
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Mizuno K, Ueno Y. Autonomic Nervous System and the Liver. Hepatol Res 2017; 47:160-165. [PMID: 27272272 DOI: 10.1111/hepr.12760] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 12/14/2022]
Abstract
The liver is innervated by both the sympathetic and the parasympathetic nerve systems. These nerves are derived from the splanchnic and vagal nerves that surround the portal vein, hepatic artery, and bile duct. The afferent fiber delivers information regarding osmolality, glucose level, and lipid level in the portal vein to the central nervous system (CNS). In contrast, the efferent fiber is crucial in the regulation of metabolism, blood flow, and bile secretion. Furthermore, liver innervation has been associated with hepatic fibrosis, regeneration, and circadian rhythm. Knowledge of these mechanisms can be applied for potential liver disease treatment.
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Affiliation(s)
- Kei Mizuno
- Department of Gastroenterology, Yamagata University Faculty of Medicine.,CREST, Yamagata, Japan
| | - Yoshiyuki Ueno
- Department of Gastroenterology, Yamagata University Faculty of Medicine.,CREST, Yamagata, Japan
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164
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Rieusset J. Endoplasmic reticulum-mitochondria calcium signaling in hepatic metabolic diseases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:865-876. [PMID: 28064001 DOI: 10.1016/j.bbamcr.2017.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 02/07/2023]
Abstract
The liver plays a central role in glucose homeostasis, and both metabolic inflexibility and insulin resistance predispose to the development of hepatic metabolic diseases. Mitochondria and endoplasmic reticulum (ER), which play a key role in the control of hepatic metabolism, also interact at contact points defined as mitochondria-associated membranes (MAM), in order to exchange metabolites and calcium (Ca2+) and regulate cellular homeostasis and signaling. Here, we overview the role of the liver in the control of glucose homeostasis, mainly focusing on the independent involvement of mitochondria, ER and Ca2+ signaling in both healthy and pathological contexts. Then we focus on recent data highlighting MAM as important hubs for hormone and nutrient signaling in the liver, thus adapting mitochondria physiology and cellular metabolism to energy availability. Lastly, we discuss how chronic ER-mitochondria miscommunication could participate to hepatic metabolic diseases, pointing MAM interface as a potential therapeutic target for metabolic disorders. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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165
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Sacramento JF, Ribeiro MJ, Rodrigues T, Olea E, Melo BF, Guarino MP, Fonseca-Pinto R, Ferreira CR, Coelho J, Obeso A, Seiça R, Matafome P, Conde SV. Functional abolition of carotid body activity restores insulin action and glucose homeostasis in rats: key roles for visceral adipose tissue and the liver. Diabetologia 2017; 60:158-168. [PMID: 27744526 DOI: 10.1007/s00125-016-4133-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
Abstract
AIMS/HYPOTHESIS We recently described that carotid body (CB) over-activation is involved in the aetiology of insulin resistance and arterial hypertension in animal models of the metabolic syndrome. Additionally, we have demonstrated that CB activity is increased in animal models of insulin resistance, and that carotid sinus nerve (CSN) resection prevents the development of insulin resistance and arterial hypertension induced by high-energy diets. Here, we tested whether the functional abolition of CB by CSN transection would reverse pre-established insulin resistance, dyslipidaemia, obesity, autonomic dysfunction and hypertension in animal models of the metabolic syndrome. The effect of CSN resection on insulin signalling pathways and tissue-specific glucose uptake was evaluated in skeletal muscle, adipose tissue and liver. METHODS Experiments were performed in male Wistar rats submitted to two high-energy diets: a high-fat diet, representing a model of insulin resistance, hypertension and obesity, and a high-sucrose diet, representing a lean model of insulin resistance and hypertension. Half of each group was submitted to chronic bilateral resection of the CSN. Age-matched control rats were also used. RESULTS CSN resection normalised systemic sympathetic nervous system activity and reversed weight gain induced by high-energy diets. It also normalised plasma glucose and insulin levels, insulin sensitivity lipid profile, arterial pressure and endothelial function by improving glucose uptake by the liver and perienteric adipose tissue. CONCLUSIONS/INTERPRETATION We concluded that functional abolition of CB activity restores insulin sensitivity and glucose homeostasis by positively affecting insulin signalling pathways in visceral adipose tissue and liver.
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Affiliation(s)
- Joana F Sacramento
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Maria J Ribeiro
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Tiago Rodrigues
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
| | - Elena Olea
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina. Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Salud Carlos III (ISCIII), Valladolid, España
| | - Bernardete F Melo
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Maria P Guarino
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
- Unidade de Investigação em Saúde (UIS), Escola Superior de Saúde de Leiria, Instituto Politécnico de Leiria, Leiria, Portugal
| | - Rui Fonseca-Pinto
- Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Leiria, Leiria, Portugal
- Instituto de Telecomunicações, Leiria, Portugal
| | - Cristiana R Ferreira
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Joana Coelho
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina. Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Salud Carlos III (ISCIII), Valladolid, España
| | - Raquel Seiça
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
| | - Paulo Matafome
- Laboratório de Fisiologia, Instituto Biomédico de Investigação de Luz e Imagem (IBILI), Faculdade de Medicina, Universidade de Coimbra, Coimbra, Portugal
- Instituto Politécnico de Coimbra, Escola Superior de Tecnologia da Saúde (ESTeSC), Departmento de Ciências Complementares, Coimbra, Portugal
| | - Sílvia V Conde
- Centro Estudos Doenças Crónicas (CEDOC), Faculdade Ciências Médicas, NOVA Medical School, Universidade Nova de Lisboa, Rua Camara Pestana, 6-6a, Edificio II, piso 3, 1150-082, Lisboa, Portugal.
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166
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Wesolowski SR, Hay WW. Role of placental insufficiency and intrauterine growth restriction on the activation of fetal hepatic glucose production. Mol Cell Endocrinol 2016; 435:61-68. [PMID: 26723529 PMCID: PMC4921201 DOI: 10.1016/j.mce.2015.12.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023]
Abstract
Glucose is the major fuel for fetal oxidative metabolism. A positive maternal-fetal glucose gradient drives glucose across the placenta and is sufficient to meet the demands of the fetus, eliminating the need for endogenous hepatic glucose production (HGP). However, fetuses with intrauterine growth restriction (IUGR) from pregnancies complicated by placental insufficiency have an early activation of HGP. Furthermore, this activated HGP is resistant to suppression by insulin. Here, we present the data demonstrating the activation of HGP in animal models, mostly fetal sheep, and human pregnancies with IUGR. We also discuss potential mechanisms and pathways that may produce and support HGP and hepatic insulin resistance in IUGR fetuses.
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Affiliation(s)
- Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA
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167
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Aydemir TB, Troche C, Kim MH, Cousins RJ. Hepatic ZIP14-mediated Zinc Transport Contributes to Endosomal Insulin Receptor Trafficking and Glucose Metabolism. J Biol Chem 2016; 291:23939-23951. [PMID: 27703010 DOI: 10.1074/jbc.m116.748632] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/12/2016] [Indexed: 12/12/2022] Open
Abstract
Zinc influences signaling pathways through controlled targeted zinc transport. Zinc transporter Zip14 KO mice display a phenotype that includes impaired intestinal barrier function with low grade chronic inflammation, hyperinsulinemia, and increased body fat, which are signatures of diet-induced diabetes (type 2 diabetes) and obesity in humans. Hyperglycemia in type 2 diabetes and obesity is caused by insulin resistance. Insulin resistance results in inhibition of glucose uptake by liver and other peripheral tissues, principally adipose and muscle and with concurrently higher hepatic glucose production. Therefore, modulation of hepatic glucose metabolism is an important target for antidiabetic treatment approaches. We demonstrate that during glucose uptake, cell surface abundance of zinc transporter ZIP14 and mediated zinc transport increases. Zinc is distributed to multiple sites in hepatocytes through sequential translocation of ZIP14 from plasma membrane to early and late endosomes. Endosomes from Zip14 KO mice were zinc-deficient because activities of the zinc-dependent insulin-degrading proteases insulin-degrading enzyme and cathepsin D were impaired; hence insulin receptor activity increased. Transient increases in cytosolic zinc levels are concurrent with glucose uptake and suppression of glycogen synthesis. In contrast, Zip14 KO mice exhibited greater hepatic glycogen synthesis and impaired gluconeogenesis and glycolysis related to low cytosolic zinc levels. We can conclude that ZIP14-mediated zinc transport contributes to regulation of endosomal insulin receptor activity and glucose homeostasis in hepatocytes. Therefore, modulation of ZIP14 transport activity presents a new target for management of diabetes and other glucose-related disorders.
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Affiliation(s)
- Tolunay Beker Aydemir
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Catalina Troche
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Min-Hyun Kim
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Robert J Cousins
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and .,the Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida 32611
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168
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Geisler CE, Hepler C, Higgins MR, Renquist BJ. Hepatic adaptations to maintain metabolic homeostasis in response to fasting and refeeding in mice. Nutr Metab (Lond) 2016; 13:62. [PMID: 27708682 PMCID: PMC5037643 DOI: 10.1186/s12986-016-0122-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 09/15/2016] [Indexed: 12/26/2022] Open
Abstract
Background The increased incidence of obesity and associated metabolic diseases has driven research focused on genetically or pharmacologically alleviating metabolic dysfunction. These studies employ a range of fasting-refeeding models including 4–24 h fasts, “overnight” fasts, or meal feeding. Still, we lack literature that describes the physiologically relevant adaptations that accompany changes in the duration of fasting and re-feeding. Since the liver is central to whole body metabolic homeostasis, we investigated the timing of the fast-induced shift toward glycogenolysis, gluconeogenesis, and ketogenesis and the meal-induced switch toward glycogenesis and away from ketogenesis. Methods Twelve to fourteen week old male C57BL/6J mice were fasted for 0, 4, 8, 12, or 16 h and sacrificed 4 h after lights on. In a second study, designed to understand the response to a meal, we gave fasted mice access to feed for 1 or 2 h before sacrifice. We analyzed the data using mixed model analysis of variance. Results Fasting initiated robust metabolic shifts, evidenced by changes in serum glucose, non-esterified fatty acids (NEFAs), triacylglycerol, and β-OH butyrate, as well as, liver triacylglycerol, non-esterified fatty acid, and glycogen content. Glycogenolysis is the primary source to maintain serum glucose during the first 8 h of fasting, while de novo gluconeogenesis is the primary source thereafter. The increase in serum β-OH butyrate results from increased enzymatic capacity for fatty acid flux through β-oxidation and shunting of acetyl-CoA toward ketone body synthesis (increased CPT1 (Carnitine Palmitoyltransferase 1) and HMGCS2 (3-Hydroxy-3-Methylglutaryl-CoA Synthase 2) expression, respectively). In opposition to the relatively slow metabolic adaptation to fasting, feeding of a meal results in rapid metabolic changes including full depression of serum β-OH butyrate and NEFAs within an hour. Conclusions Herein, we provide a detailed description of timing of the metabolic adaptations in response to fasting and re-feeding to inform study design in experiments of metabolic homeostasis. Since fasting and obesity are both characterized by elevated adipose tissue lipolysis, hepatic lipid accumulation, ketogenesis, and gluconeogenesis, understanding the drivers behind the metabolic shift from the fasted to the fed state may provide targets to limit aberrant gluconeogenesis and ketogenesis in obesity.
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Affiliation(s)
- C E Geisler
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
| | - C Hepler
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75235 USA
| | - M R Higgins
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
| | - B J Renquist
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
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169
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Rines AK, Sharabi K, Tavares CDJ, Puigserver P. Targeting hepatic glucose metabolism in the treatment of type 2 diabetes. Nat Rev Drug Discov 2016; 15:786-804. [PMID: 27516169 DOI: 10.1038/nrd.2016.151] [Citation(s) in RCA: 224] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus is characterized by the dysregulation of glucose homeostasis, resulting in hyperglycaemia. Although current diabetes treatments have exhibited some success in lowering blood glucose levels, their effect is not always sustained and their use may be associated with undesirable side effects, such as hypoglycaemia. Novel antidiabetic drugs, which may be used in combination with existing therapies, are therefore needed. The potential of specifically targeting the liver to normalize blood glucose levels has not been fully exploited. Here, we review the molecular mechanisms controlling hepatic gluconeogenesis and glycogen storage, and assess the prospect of therapeutically targeting associated pathways to treat type 2 diabetes.
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Affiliation(s)
- Amy K Rines
- Department of Cancer Biology, Dana-Farber Cancer Institute, and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kfir Sharabi
- Department of Cancer Biology, Dana-Farber Cancer Institute, and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Clint D J Tavares
- Department of Cancer Biology, Dana-Farber Cancer Institute, and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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170
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Meireles P, Sales-Dias J, Andrade CM, Mello-Vieira J, Mancio-Silva L, Simas JP, Staines HM, Prudêncio M. GLUT1-mediated glucose uptake plays a crucial role during Plasmodium hepatic infection. Cell Microbiol 2016; 19. [PMID: 27404888 PMCID: PMC5297879 DOI: 10.1111/cmi.12646] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 06/20/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023]
Abstract
Intracellular pathogens have evolved mechanisms to ensure their survival and development inside their host cells. Here, we show that glucose is a pivotal modulator of hepatic infection by the rodent malaria parasite Plasmodium berghei and that glucose uptake via the GLUT1 transporter is specifically enhanced in P. berghei‐infected cells. We further show that ATP levels of cells containing developing parasites are decreased, which is known to enhance membrane GLUT1 activity. In addition, GLUT1 molecules are translocated to the membrane of the hepatic cell, increasing glucose uptake at later stages of infection. Chemical inhibition of GLUT1 activity leads to a decrease in glucose uptake and the consequent impairment of hepatic infection, both in vitro and in vivo. Our results reveal that changes in GLUT1 conformation and cellular localization seem to be part of an adaptive host response to maintain adequate cellular nutrition and energy levels, ensuring host cell survival and supporting P. berghei hepatic development.
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Affiliation(s)
- Patrícia Meireles
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joana Sales-Dias
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Carolina M Andrade
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - João Mello-Vieira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Liliana Mancio-Silva
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - J Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Henry M Staines
- Institute for Infection & Immunity, St. George's, University of London, Cranmer Terrace, London, UK
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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171
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Affiliation(s)
- Loranne Agius
- Institutes of Cellular Medicine and Ageing and Health, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH United Kingdom;
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172
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Scarlett JM, Rojas JM, Matsen ME, Kaiyala KJ, Stefanovski D, Bergman RN, Nguyen HT, Dorfman MD, Lantier L, Wasserman DH, Mirzadeh Z, Unterman TG, Morton GJ, Schwartz MW. Central injection of fibroblast growth factor 1 induces sustained remission of diabetic hyperglycemia in rodents. Nat Med 2016; 22:800-6. [PMID: 27213816 PMCID: PMC4938755 DOI: 10.1038/nm.4101] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 04/08/2016] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes (T2D) is among the most common and costly disorders worldwide. The goal of current medical management for T2D is to transiently ameliorate hyperglycemia through daily dosing of one or more antidiabetic drugs. Hypoglycemia and weight gain are common side effects of therapy, and sustained disease remission is not obtainable with nonsurgical approaches. On the basis of the potent glucose-lowering response elicited by activation of brain fibroblast growth factor (FGF) receptors, we explored the antidiabetic efficacy of centrally administered FGF1, which, unlike other FGF peptides, activates all FGF receptor subtypes. We report that a single intracerebroventricular injection of FGF1 at a dose one-tenth of that needed for antidiabetic efficacy following peripheral injection induces sustained diabetes remission in both mouse and rat models of T2D. This antidiabetic effect is not secondary to weight loss, does not increase the risk of hypoglycemia, and involves a novel and incompletely understood mechanism for increasing glucose clearance from the bloodstream. We conclude that the brain has an inherent potential to induce diabetes remission and that brain FGF receptors are potential pharmacological targets for achieving this goal.
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MESH Headings
- Adipose Tissue/drug effects
- Adipose Tissue/metabolism
- Animals
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Blotting, Western
- Body Composition
- Brain/drug effects
- Brain/metabolism
- Carbon Radioisotopes
- Deoxyglucose
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/metabolism
- Diet, High-Fat
- Disease Models, Animal
- Ependymoglial Cells/drug effects
- Ependymoglial Cells/metabolism
- Fibroblast Growth Factor 1/pharmacology
- Forkhead Box Protein O1/genetics
- Glucose Tolerance Test
- Heart/drug effects
- Heat-Shock Proteins/drug effects
- Heat-Shock Proteins/metabolism
- Hyperglycemia/metabolism
- Hypothalamus/cytology
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Injections, Intraventricular
- Liver/metabolism
- Male
- Mice
- Mice, Knockout
- Mice, Obese
- Molecular Chaperones
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Myocardium/metabolism
- Neoplasm Proteins/drug effects
- Neoplasm Proteins/metabolism
- Proto-Oncogene Proteins c-fos/drug effects
- Proto-Oncogene Proteins c-fos/metabolism
- Rats
- Rats, Zucker
- Real-Time Polymerase Chain Reaction
- Receptor, Insulin/antagonists & inhibitors
- Receptor, Insulin/genetics
- Remission Induction
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Affiliation(s)
- Jarrad M Scarlett
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, Washington, USA
| | - Jennifer M Rojas
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Miles E Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Hong T Nguyen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Mauricio D Dorfman
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA
| | - Zaman Mirzadeh
- Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Terry G Unterman
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA
- Medical Service, Jesse Brown Virginia Medical Center, Chicago, Illinois, USA
| | - Gregory J Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Michael W Schwartz
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA
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173
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Titchenell PM, Quinn WJ, Lu M, Chu Q, Lu W, Li C, Chen H, Monks BR, Chen J, Rabinowitz JD, Birnbaum MJ. Direct Hepatocyte Insulin Signaling Is Required for Lipogenesis but Is Dispensable for the Suppression of Glucose Production. Cell Metab 2016; 23:1154-1166. [PMID: 27238637 PMCID: PMC4909537 DOI: 10.1016/j.cmet.2016.04.022] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/10/2016] [Accepted: 04/25/2016] [Indexed: 12/22/2022]
Abstract
During insulin-resistant states such as type II diabetes mellitus (T2DM), insulin fails to suppress hepatic glucose production (HGP) yet promotes lipid synthesis. This metabolic state has been termed "selective insulin resistance" to indicate a defect in one arm of the insulin-signaling cascade, potentially downstream of Akt. Here we demonstrate that Akt-dependent activation of mTORC1 and inhibition of Foxo1 are required and sufficient for de novo lipogenesis, suggesting that hepatic insulin signaling is likely to be intact in insulin-resistant states. Moreover, cell-nonautonomous suppression of HGP by insulin depends on a reduction of adipocyte lipolysis and serum FFAs but is independent of vagal efferents or glucagon signaling. These data are consistent with a model in which, during T2DM, intact liver insulin signaling drives enhanced lipogenesis while excess circulating FFAs become a dominant inducer of nonsuppressible HGP.
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Affiliation(s)
- Paul M Titchenell
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William J Quinn
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mingjian Lu
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Qingwei Chu
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wenyun Lu
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Changhong Li
- Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Helen Chen
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bobby R Monks
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julia Chen
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Morris J Birnbaum
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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174
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Le Foll C, Levin BE. Fatty acid-induced astrocyte ketone production and the control of food intake. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1186-92. [PMID: 27122369 PMCID: PMC4935491 DOI: 10.1152/ajpregu.00113.2016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/22/2016] [Indexed: 11/22/2022]
Abstract
Obesity and Type 2 diabetes are major worldwide public health issues today. A relationship between total fat intake and obesity has been found. In addition, the mechanisms of long-term and excessive high-fat diet (HFD) intake in the development of obesity still need to be elucidated. The ventromedial hypothalamus (VMH) is a major site involved in the regulation of glucose and energy homeostasis where "metabolic sensing neurons" integrate metabolic signals from the periphery. Among these signals, fatty acids (FA) modulate the activity of VMH neurons using the FA translocator/CD36, which plays a critical role in the regulation of energy and glucose homeostasis. During low-fat diet (LFD) intake, FA are oxidized by VMH astrocytes to fuel their ongoing metabolic needs. However, HFD intake causes VMH astrocytes to use FA to generate ketone bodies. We postulate that these astrocyte-derived ketone bodies are exported to neurons where they produce excess ATP and reactive oxygen species, which override CD36-mediated FA sensing and act as a signal to decrease short-term food intake. On a HFD, VMH astrocyte-produced ketones reduce elevated caloric intake to LFD levels after 3 days in rats genetically predisposed to resist (DR) diet-induced obesity (DIO), but not leptin-resistant DIO rats. This suggests that, while VMH ketone production on a HFD can contribute to protection from obesity, the inherent leptin resistance overrides this inhibitory action of ketone bodies on food intake. Thus, astrocytes and neurons form a tight metabolic unit that is able to monitor circulating nutrients to alter food intake and energy homeostasis.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; and
| | - Barry E Levin
- Department of Neurology, Rutgers, New Jersey Medical School, Newark, New Jersey
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175
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Fournel A, Marlin A, Abot A, Pasquio C, Cirillo C, Cani PD, Knauf C. Glucosensing in the gastrointestinal tract: Impact on glucose metabolism. Am J Physiol Gastrointest Liver Physiol 2016; 310:G645-58. [PMID: 26939867 PMCID: PMC4867329 DOI: 10.1152/ajpgi.00015.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/25/2016] [Indexed: 01/31/2023]
Abstract
The gastrointestinal tract is an important interface of exchange between ingested food and the body. Glucose is one of the major dietary sources of energy. All along the gastrointestinal tube, e.g., the oral cavity, small intestine, pancreas, and portal vein, specialized cells referred to as glucosensors detect variations in glucose levels. In response to this glucose detection, these cells send hormonal and neuronal messages to tissues involved in glucose metabolism to regulate glycemia. The gastrointestinal tract continuously communicates with the brain, especially with the hypothalamus, via the gut-brain axis. It is now well established that the cross talk between the gut and the brain is of crucial importance in the control of glucose homeostasis. In addition to receiving glucosensing information from the gut, the hypothalamus may also directly sense glucose. Indeed, the hypothalamus contains glucose-sensitive cells that regulate glucose homeostasis by sending signals to peripheral tissues via the autonomous nervous system. This review summarizes the mechanisms by which glucosensors along the gastrointestinal tract detect glucose, as well as the results of such detection in the whole body, including the hypothalamus. We also highlight how disturbances in the glucosensing process may lead to metabolic disorders such as type 2 diabetes. A better understanding of the pathways regulating glucose homeostasis will further facilitate the development of novel therapeutic strategies for the treatment of metabolic diseases.
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Affiliation(s)
- Audren Fournel
- 1NeuroMicrobiota, European Associated Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) U1220, Institut de Recherche en Santé Digestive (IRSD), Toulouse, France;
| | - Alysson Marlin
- 1NeuroMicrobiota, European Associated Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) U1220, Institut de Recherche en Santé Digestive (IRSD), Toulouse, France;
| | - Anne Abot
- 1NeuroMicrobiota, European Associated Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) U1220, Institut de Recherche en Santé Digestive (IRSD), Toulouse, France;
| | - Charles Pasquio
- 1NeuroMicrobiota, European Associated Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) U1220, Institut de Recherche en Santé Digestive (IRSD), Toulouse, France;
| | - Carla Cirillo
- 2Laboratory for Enteric NeuroScience (LENS), University of Leuven, Leuven, Belgium; and
| | - Patrice D. Cani
- 3NeuroMicrobiota, European Associated Laboratory, Université Catholique de Louvain (UCL), Louvain Drug Research Institute (LDRI), Metabolism and Nutrition Research Group, WELBIO (Walloon Excellence in Life sciences and BIOtechnology), Brussels, Belgium
| | - Claude Knauf
- NeuroMicrobiota, European Associated Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) U1220, Institut de Recherche en Santé Digestive (IRSD), Toulouse, France;
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176
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Abstract
Angiopoietin-like protein 3 (ANGPTL3) is a secretory protein regulating plasma lipid levels via affecting lipoprotein lipase- and endothelial lipase-mediated hydrolysis of triglycerides and phospholipids. ANGPTL3-deficiency due to loss-of-function mutations in the ANGPTL3 gene causes familial combined hypobetalipoproteinemia (FHBL2, OMIM # 605019), a phenotype characterized by low concentration of all major lipoprotein classes in circulation. ANGPTL3 is therefore a potential therapeutic target to treat combined hyperlipidemia, a major risk factor for atherosclerotic coronary heart disease. This review focuses on the mechanisms behind ANGPTL3-deficiency induced FHBL2.
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Affiliation(s)
- Anna Tikka
- National Institute for Health and Welfare. Genomics and Biomarkers Unit, Biomedicum, Haartmaninkatu 8, 00250, Helsinki, Finland.
| | - Matti Jauhiainen
- National Institute for Health and Welfare. Genomics and Biomarkers Unit, Biomedicum, Haartmaninkatu 8, 00250, Helsinki, Finland
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177
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Naftalin RJ. A computer model simulating human glucose absorption and metabolism in health and metabolic disease states. F1000Res 2016; 5:647. [PMID: 27347379 PMCID: PMC4909112 DOI: 10.12688/f1000research.8299.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2016] [Indexed: 12/16/2022] Open
Abstract
A computer model designed to simulate integrated glucose-dependent changes in splanchnic blood flow with small intestinal glucose absorption, hormonal and incretin circulation and hepatic and systemic metabolism in health and metabolic diseases e.g. non-alcoholic fatty liver disease, (NAFLD), non-alcoholic steatohepatitis, (NASH) and type 2 diabetes mellitus, (T2DM) demonstrates how when glucagon-like peptide-1, (GLP-1) is synchronously released into the splanchnic blood during intestinal glucose absorption, it stimulates superior mesenteric arterial (SMA) blood flow and by increasing passive intestinal glucose absorption, harmonizes absorption with its distribution and metabolism. GLP-1 also synergises insulin-dependent net hepatic glucose uptake (NHGU). When GLP-1 secretion is deficient post-prandial SMA blood flow is not increased and as NHGU is also reduced, hyperglycaemia follows. Portal venous glucose concentration is also raised, thereby retarding the passive component of intestinal glucose absorption. Increased pre-hepatic sinusoidal resistance combined with portal hypertension leading to opening of intrahepatic portosystemic collateral vessels are NASH-related mechanical defects that alter the balance between splanchnic and systemic distributions of glucose, hormones and incretins.The model reveals the latent contribution of portosystemic shunting in development of metabolic disease. This diverts splanchnic blood content away from the hepatic sinuses to the systemic circulation, particularly during the glucose absorptive phase of digestion, resulting in inappropriate increases in insulin-dependent systemic glucose metabolism. This hastens onset of hypoglycaemia and thence hyperglucagonaemia. The model reveals that low rates of GLP-1 secretion, frequently associated with T2DM and NASH, may be also be caused by splanchnic hypoglycaemia, rather than to intrinsic loss of incretin secretory capacity. These findings may have therapeutic implications on GLP-1 agonist or glucagon antagonist usage.
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Affiliation(s)
- Richard J Naftalin
- Departments of Physiology and Vascular Biology, BHF centre of research excellence, King's College London School of Medicine, London, UK
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178
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Nutritional regulation of the anabolic fate of amino acids within the liver in mammals: concepts arising from in vivo studies. Nutr Res Rev 2016; 28:22-41. [PMID: 26156215 DOI: 10.1017/s0954422415000013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
At the crossroad between nutrient supply and requirements, the liver plays a central role in partitioning nitrogenous nutrients among tissues. The present review examines the utilisation of amino acids (AA) within the liver in various physiopathological states in mammals and how the fates of AA are regulated. AA uptake by the liver is generally driven by the net portal appearance of AA. This coordination is lost when demands by peripheral tissues is important (rapid growth or lactation), or when certain metabolic pathways within the liver become a priority (synthesis of acute-phase proteins). Data obtained in various species have shown that oxidation of AA and export protein synthesis usually responds to nutrient supply. Gluconeogenesis from AA is less dependent on hepatic delivery and the nature of nutrients supplied, and hormones like insulin are involved in the regulatory processes. Gluconeogenesis is regulated by nutritional factors very differently between mammals (glucose absorbed from the diet is important in single-stomached animals, while in carnivores, glucose from endogenous origin is key). The underlying mechanisms explaining how the liver adapts its AA utilisation to the body requirements are complex. The highly adaptable hepatic metabolism must be capable to deal with the various nutritional/physiological challenges that mammals have to face to maintain homeostasis. Whereas the liver responds generally to nutritional parameters in various physiological states occurring throughout life, other complex signalling pathways at systemic and tissue level (hormones, cytokines, nutrients, etc.) are involved additionally in specific physiological/nutritional states to prioritise certain metabolic pathways (pathological states or when nutritional requirements are uncovered).
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179
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Madsbad S. Impact of postprandial glucose control on diabetes-related complications: How is the evidence evolving? J Diabetes Complications 2016; 30:374-85. [PMID: 26541075 DOI: 10.1016/j.jdiacomp.2015.09.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 12/14/2022]
Abstract
Conflicting findings in the literature and lack of long-term definitive outcome studies have led to difficulty in drawing conclusions about the role of postprandial hyperglycemia in diabetes and its complications. Recent scientific publications support the role of postprandial glucose (PPG) as a key contributor to overall glucose control and a predictor of microvascular and macrovascular events. However, the need remains for definitive evidence to support the precise relationship between PPG excursions and the development and progression of cardiovascular complications of diabetes. Drawing firm conclusions on the relationship between PPG and microvascular and macrovascular complications is challenged by the absence of antidiabetic agents that can specifically exert their action on PPG alone, without a basal glucose-lowering effect. Areas under investigation include interventions that more closely approximate 'normal' physiological postprandial responses, as well as technologies that advance the mode of insulin delivery or optimize methods to sense glycemic levels and variation. In conclusion, the precise role of postprandial hyperglycemia in relation to development of diabetic complications is unclarified and is one of the remaining unanswered questions in diabetes. Nevertheless, current evidence supports PPG control as an important strategy to consider in the comprehensive management plan of individuals with diabetes.
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Affiliation(s)
- Sten Madsbad
- Department of Endocrinology, Hvidovre University Hospital, University of Copenhagen, Denmark.
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180
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Singh P, Irwin DM. Contrasting Patterns in the Evolution of Vertebrate MLX Interacting Protein (MLXIP) and MLX Interacting Protein-Like (MLXIPL) Genes. PLoS One 2016; 11:e0149682. [PMID: 26910886 PMCID: PMC4766361 DOI: 10.1371/journal.pone.0149682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/03/2016] [Indexed: 01/09/2023] Open
Abstract
ChREBP and MondoA are glucose-sensitive transcription factors that regulate aspects of energy metabolism. Here we performed a phylogenomic analysis of Mlxip (encoding MondoA) and Mlxipl (encoding ChREBP) genes across vertebrates. Analysis of extant Mlxip and Mlxipl genes suggests that the most recent common ancestor of these genes was composed of 17 coding exons. Single copy genes encoding both ChREBP and MondoA, along with their interacting partner Mlx, were found in diverse vertebrate genomes, including fish that have experienced a genome duplication. This observation suggests that a single Mlx gene has been retained to maintain coordinate regulation of ChREBP and MondoA. The ChREBP-β isoform, the more potent and constitutively active isoform, appeared with the evolution of tetrapods and is absent from the Mlxipl genes of fish. Evaluation of the conservation of ChREBP and MondoA sequences demonstrate that MondoA is better conserved and potentially mediates more ancient function in glucose metabolism.
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Affiliation(s)
- Parmveer Singh
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - David M. Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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181
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Abstract
OBJECTIVE Hyperglycemia has been shown to influence fluorine-18 fluorodeoxyglucose ((18)F-FDG) uptake in tumor cells. Therefore, patients are instructed to fast for 6 h, while maintaining serum glucose levels at an acceptable range. The study was performed to evaluate the effect of fasting blood glucose levels on the biodistribution of (18)F-FDG in various tissues including the liver, heart, bone marrow, skeletal muscle, and tumors. MATERIALS AND METHODS Fingerstick fasting blood glucose is routinely measured on the morning of the procedure. The maximum standardized uptake value (SUV(max)) in the right and left hepatic lobes, left ventricle, sacrum, thigh, and tumor was measured in 229 consecutive patients undergoing (18)F-FDG PET/computed tomography for tumor. Patients were divided into three groups depending on their serum glucose levels: low (<100; n = 53), medium (100-160; n = 149), and high (160-201; n = 27). A retrospective analysis of the relationship between glucose levels and standardized uptake value was performed. RESULTS There was a statistically significant increase in the average SUV(max) in the right and left hepatic lobes as glucose levels increased (right lobe P=0.00144; left lobe P = 0.03889). Subsequently, pairwise analysis was performed, revealing a statistically significant increase in SUV(max) in the right hepatic lobe between low-glucose and medium-glucose groups and in both hepatic lobes between low and high groups (P < 0.017). No significant difference was observed in any of the other measured tissues. CONCLUSION This study shows a directly proportional relationship between blood glucose levels and nonpathologic (18)F-FDG biodistribution in the right and left hepatic lobes. The influence of blood glucose on expected biodistribution patterns, particularly in the liver, should be considered during interpretation.
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182
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Xie C, Wang Q, Wang J, Tan B, Fan Z, Deng ZY, Wu X, Yin Y. Developmental changes in hepatic glucose metabolism in a newborn piglet model: A comparative analysis for suckling period and early weaning period. Biochem Biophys Res Commun 2016; 470:824-30. [PMID: 26802463 DOI: 10.1016/j.bbrc.2016.01.114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 01/19/2016] [Indexed: 02/07/2023]
Abstract
The liver glucose metabolism, supplying sufficient energy for glucose-dependent tissues, is important in suckling or weaned animals, although there are few studies with piglet model. To better understand the development of glucose metabolism in the piglets during suckling period and early weaning period, we determined the hepatic glycogen content, and investigated the relative protein expression of key enzymes of glucogenesis (GNG) and mRNA levels of some glucose metabolism-related genes. During suckling period, the protein level of G6Pase in the liver of suckling piglets progressively declined with day of age compared with that of newborn piglets (at 1 day of age), whereas the PEPCK level stabilized until day 21 of age, indicating that hepatic GNG capacity gradually weakened in suckling piglets. The synthesis of hepatic glycogen, which was consistent with the fluctuation of glycolytic key genes PFKL and PKLR that gradually decreased after birth and was more or less steady during latter suckling period, although both the mRNA levels of GCK and key glucose transporter GLUT2 presented uptrend in suckling piglets. However, early weaning significantly suppressed the hepatic GNG in the weaned piglets, especially at d 3-5 of weaning period, then gradually recovered at d 7 of weaning period. Meanwhile, PFKL, PKLR and GLUT2 showed the similar trend during weaning period. On the contrast, the hepatic glycogen reached the maximum value when the G6Pase and PEPCK protein expression were at the lowest level, although the GCK level maintained increasing through 7 days of weaning period. Altogether, our study provides evidence that hepatic GNG and glycolysis in newborn piglets were more active than other days during suckling period, and early weaning could significantly suppressed glucose metabolism in liver, but this inhibition would progressively recover at day 7 after weaning.
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Affiliation(s)
- Chunyan Xie
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; University of the Chinese Academy of Sciences, Beijing, 10008, China
| | - Qinhua Wang
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha, 410128, China
| | - Jing Wang
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; University of the Chinese Academy of Sciences, Beijing, 10008, China
| | - Bie Tan
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha, 410128, China
| | - Zhiyong Fan
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha, 410128, China
| | - Ze-yuan Deng
- State Key Laboratory of Food Science and Technology and College of Life Science and Food Engineering, Nanchang University, Nanchang, Jiangxi, 330031, China
| | - Xin Wu
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha, 410128, China; State Key Laboratory of Food Science and Technology and College of Life Science and Food Engineering, Nanchang University, Nanchang, Jiangxi, 330031, China.
| | - Yulong Yin
- Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China; Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha, 410128, China; State Key Laboratory of Food Science and Technology and College of Life Science and Food Engineering, Nanchang University, Nanchang, Jiangxi, 330031, China; School of Life Sciences, Hunan Normal University, Changsha, 41008, China; University of the Chinese Academy of Sciences, Beijing, 10008, China.
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183
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Matravadia S, Zabielski P, Chabowski A, Mutch DM, Holloway GP. LA and ALA prevent glucose intolerance in obese male rats without reducing reactive lipid content, but cause tissue-specific changes in fatty acid composition. Am J Physiol Regul Integr Comp Physiol 2016; 310:R619-30. [PMID: 26764053 DOI: 10.1152/ajpregu.00297.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 01/12/2016] [Indexed: 12/18/2022]
Abstract
While the cause of Type 2 diabetes remains poorly defined, the accumulation of reactive lipids within white adipose tissue, skeletal muscle, and liver have been repeatedly implicated as underlying mechanisms. The ability of polyunsaturated fatty acids (PUFAs) to prevent the development of insulin resistance has gained considerable interest in recent years; however, the mechanisms-of-action remain poorly described. Therefore, we determined the efficacy of diets supplemented with either linoleic acid (LA) or α-linolenic acid (ALA) in preventing insulin resistance and reactive lipid accumulation in key metabolic tissues of the obese Zucker rat. Obese Zucker rats displayed impaired glucose homeostasis and reduced n-3 and n-6 PUFA content in the liver and epididymal white adipose tissue (EWAT). After the 12-wk feeding intervention, both LA- and ALA-supplemented diets prevented whole body glucose and insulin intolerance; however, ALA had a more pronounced effect. These changes occurred in association with n-3 and n-6 accumulation in all tissues studied, albeit to different extents (EWAT > liver > muscle). Triacylglycerol (TAG), diacylglycerol (DAG), ceramide, and sphingolipid accumulation were not attenuated in obese animals supplemented with either LA or ALA, suggesting that preservation of glucose homeostasis occurred independent of changes in reactive lipid content. However, PUFA-supplemented diets differentially altered the fatty acid composition of TAGs, DAGs, and PLs in a tissue-specific manner, suggesting essential fatty acid metabolism differs between tissues. Together, our results indicate that remodeling of the fatty acid composition of various lipid fractions may contribute to the improved glucose tolerance observed in obese rats fed PUFA-supplemented diets.
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Affiliation(s)
- Sarthak Matravadia
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Piotr Zabielski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
| | - Adrian Chabowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
| | - David M Mutch
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada;
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184
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Honka MJ, Bucci M, Andersson J, Huovinen V, Guzzardi MA, Sandboge S, Savisto N, Salonen MK, Badeau RM, Parkkola R, Kullberg J, Iozzo P, Eriksson JG, Nuutila P. Resistance training enhances insulin suppression of endogenous glucose production in elderly women. J Appl Physiol (1985) 2016; 120:633-9. [PMID: 26744506 DOI: 10.1152/japplphysiol.00950.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/30/2015] [Indexed: 11/22/2022] Open
Abstract
An altered prenatal environment during maternal obesity predisposes offspring to insulin resistance, obesity, and their consequent comorbidities, type 2 diabetes and cardiovascular disease. Telomere shortening and frailty are additional risk factors for these conditions. The aim of this study was to evaluate the effects of resistance training on hepatic metabolism and ectopic fat accumulation. Thirty-five frail elderly women, whose mothers' body mass index (BMI) was known, participated in a 4-mo resistance training program. Endogenous glucose production (EGP) and hepatic and visceral fat glucose uptake were measured during euglycemic hyperinsulinemia with [(18)F]fluorodeoxyglucose and positron emission tomography. Ectopic fat was measured using magnetic resonance spectroscopy and imaging. We found that the training intervention reduced EGP during insulin stimulation [from 5.4 (interquartile range 3.0, 7.0) to 3.9 (-0.4, 6.1) μmol·kg body wt(-1)·min(-1), P = 0.042] in the whole study group. Importantly, the reduction was higher among those whose EGP was more insulin resistant at baseline (higher than the median) [-5.6 (7.1) vs. 0.1 (5.4) μmol·kg body wt(-1)·min(-1), P = 0.015]. Furthermore, the decrease in EGP was associated with telomere elongation (r = -0.620, P = 0.001). The resistance training intervention did not change either hepatic or visceral fat glucose uptake or the amounts of ectopic fat. Maternal obesity did not influence the studied measures. In conclusion, resistance training improves suppression of EGP in elderly women. The finding of improved insulin sensitivity of EGP with associated telomere lengthening implies that elderly women can reduce their risk for type 2 diabetes and cardiovascular disease with resistance training.
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Affiliation(s)
| | - Marco Bucci
- Turku PET Centre, University of Turku, Turku, Finland
| | | | - Ville Huovinen
- Turku PET Centre, University of Turku, Turku, Finland; Department of Radiology, University of Turku, Turku, Finland; Department of Radiology, Turku University Hospital, Turku, Finland
| | | | - Samuel Sandboge
- Department of Chronic Disease Prevention, National Institute of Health and Welfare, Helsinki, Finland; Folkhälsan Research Center, Helsinki, Finland
| | - Nina Savisto
- Turku PET Centre, University of Turku, Turku, Finland
| | - Minna K Salonen
- Department of Chronic Disease Prevention, National Institute of Health and Welfare, Helsinki, Finland; Folkhälsan Research Center, Helsinki, Finland
| | | | - Riitta Parkkola
- Department of Radiology, University of Turku, Turku, Finland; Department of Radiology, Turku University Hospital, Turku, Finland
| | - Joel Kullberg
- Department of Radiology, Uppsala University, Uppsala, Sweden
| | - Patricia Iozzo
- Turku PET Centre, University of Turku, Turku, Finland; Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Johan G Eriksson
- Department of Chronic Disease Prevention, National Institute of Health and Welfare, Helsinki, Finland; Folkhälsan Research Center, Helsinki, Finland; Unit of General Practice, Hospital District of Helsinki and Uusimaa, Helsinki, Finland; Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland; and
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland; Department of Endocrinology, Turku University Hospital, Turku, Finland
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185
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Elango B, Dornadula S, Paulmurugan R, Ramkumar KM. Pterostilbene Ameliorates Streptozotocin-Induced Diabetes through Enhancing Antioxidant Signaling Pathways Mediated by Nrf2. Chem Res Toxicol 2016; 29:47-57. [DOI: 10.1021/acs.chemrestox.5b00378] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | | | - Ramasamy Paulmurugan
- Department
of Radiology, Stanford University School of Medicine, Palo Alto, California 94305, United States
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186
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Yu EN, Winnick JJ, Edgerton DS, Scott MF, Smith MS, Farmer B, Williams PE, Cherrington AD, Moore MC. Hepatic and Whole-Body Insulin Metabolism during Proestrus and Estrus in Mongrel Dogs. Comp Med 2016; 66:235-240. [PMID: 27298249 PMCID: PMC4907533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/11/2015] [Accepted: 10/22/2015] [Indexed: 06/06/2023]
Abstract
Insulin resistance occurs during various stages of the estrus cycle in dogs. To quantify the effects of proestrus-estrus (PE) and determine whether PE affects liver insulin sensitivity, 11 female mongrel dogs were implanted with sampling and intraportal infusion catheters. Five of the dogs (PE group) entered proestrus after surgery; those remaining in anestrus were controls. The dogs were fasted overnight, [3-(3)H]glucose and somatostatin were infused through peripheral veins, and glucagon was infused intraportally. Insulin was infused intraportally, with the rate adjusted to maintain arterial plasma glucose at basal levels (PE, 294±25 μU/kg/min; control, 223±21 μU/kg/min). Subsequently the insulin infusion rate was increased by 0.2 mU/kg/min for 120 min (P1) and then to 1.5 mU/kg/min for the last 120 min (P2); glucose was infused peripherally as needed to maintain euglycemia. Insulin concentrations did not differ between groups at any time; they increased 3 μU/mL over baseline during P1 and to 3 times baseline during P2. The glucose infusion rate in PE dogs during P2 was 63% of that in control dogs. Net hepatic glucose output and the endogenous glucose production rate declined 40% to 50% from baseline in both groups during P1; during P2, both groups exhibited a low rate of net hepatic glucose uptake with full suppression of endogenous glucose production. The glucose disappearance rate during P1 and P2 was 35% greater in control than PE dogs. Therefore, PE in canines is associated with loss of nonhepatic (primarily muscle) but not hepatic insulin sensitivity.
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Affiliation(s)
- Erin Nz Yu
- Departments of Pathology, Microbiology, Immunology, and Division of Animal Care, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jason J Winnick
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Dale S Edgerton
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Melanie F Scott
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Marta S Smith
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Ben Farmer
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Phillip E Williams
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alan D Cherrington
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Mary Courtney Moore
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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187
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Magkos F, Bradley D, Eagon JC, Patterson BW, Klein S. Effect of Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding on gastrointestinal metabolism of ingested glucose. Am J Clin Nutr 2016; 103:61-5. [PMID: 26607940 PMCID: PMC4691669 DOI: 10.3945/ajcn.115.116111] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/09/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Data from studies conducted in animal models suggest that intestinal glucose uptake and metabolism are upregulated after Roux-en-Y gastric bypass (RYGB) surgery, which contributes to a weight-loss-independent improvement in glycemic control. OBJECTIVE We conducted a cohort study to evaluate whether an increase in gastrointestinal metabolism of ingested glucose occurs in obese people who underwent RYGB compared with those who underwent laparoscopic adjustable gastric banding (LAGB). DESIGN A mixed meal containing stable isotope-labeled glucose was used to determine the gastrointestinal (small intestine and liver) retention, and presumably metabolism, of ingested glucose in obese subjects before and after matched weight loss (∼21%) induced by RYGB (n = 16) or LAGB (n = 9). RESULTS The total percentage of ingested glucose that appeared in the systemic circulation was slightly lower after than before RYGB (85% ± 9% and 90% ± 8%, respectively) but was slightly higher after than before LAGB (89% ± 3% and 85% ± 4%, respectively) (P-interaction < 0.05). Accordingly, gastrointestinal clearance of ingested glucose (cumulative percentage cleared over 6 h postprandially) increased after RYGB (from 10% ± 8% before to 15% ± 9% after surgery) but decreased after LAGB (from 15% ± 4% before to 11% ± 3% after surgery) (P < 0.05). Surgery-induced weight loss caused a similar decrease in the 6-h postprandial plasma glucose area under the curve in both RYGB and LAGB groups (-4% ± 9% and -6% ± 5%, respectively; P = 0.475). CONCLUSIONS These data support the notion that intestinal glucose disposal increases after RYGB surgery. However, the magnitude of the effect was small and did not result in weight-loss-independent therapeutic effects on postprandial glycemic control. This trial was registered at clinicaltrials.gov as NCT00981500.
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Affiliation(s)
- Faidon Magkos
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO; Singapore Institute for Clinical Sciences, Agency for Science, Technology, and Research (A*STAR), and Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - David Bradley
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO
| | - J Christopher Eagon
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO
| | - Bruce W Patterson
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO
| | - Samuel Klein
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO;
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188
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Mirmonsef P, Hotton AL, Gilbert D, Burgad D, Landay A, Weber KM, Cohen M, Ravel J, Spear GT. Free glycogen in vaginal fluids is associated with Lactobacillus colonization and low vaginal pH. PLoS One 2015. [PMID: 25033265 DOI: 10.1371/joumal.pone.0102467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
OBJECTIVE Lactobacillus dominates the lower genital tract microbiota of many women, producing a low vaginal pH, and is important for healthy pregnancy outcomes and protection against several sexually transmitted pathogens. Yet, factors that promote Lactobacillus remain poorly understood. We hypothesized that the amount of free glycogen in the lumen of the lower genital tract is an important determinant of Lactobacillus colonization and a low vaginal pH. METHODS Free glycogen in lavage samples was quantified. Pyrosequencing of the 16S rRNA gene was used to identify microbiota from 21 African American women collected over 8-11 years. RESULTS Free glycogen levels varied greatly between women and even in the same woman. Samples with the highest free glycogen had a corresponding median genital pH that was significantly lower (pH 4.4) than those with low glycogen (pH 5.8; p<0.001). The fraction of the microbiota consisting of Lactobacillus was highest in samples with high glycogen versus those with low glycogen (median = 0.97 vs. 0.05, p<0.001). In multivariable analysis, having 1 vs. 0 male sexual partner in the past 6 months was negatively associated, while BMI ≥30 was positively associated with glycogen. High concentrations of glycogen corresponded to higher levels of L. crispatus and L. jensenii, but not L. iners. CONCLUSION These findings show that free glycogen in genital fluid is associated with a genital microbiota dominated by Lactobacillus, suggesting glycogen is important for maintaining genital health. Treatments aimed at increasing genital free glycogen might impact Lactobacillus colonization.
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Affiliation(s)
- Paria Mirmonsef
- Department of Immunology/Microbiology, Rush University, Chicago, Illinois, United States of America
| | - Anna L Hotton
- The CORE Center, Cook County Health & Hospital System, Chicago, Illinois, United States of America
| | - Douglas Gilbert
- Department of Immunology/Microbiology, Rush University, Chicago, Illinois, United States of America
| | - Derick Burgad
- Department of Immunology/Microbiology, Rush University, Chicago, Illinois, United States of America
| | - Alan Landay
- Department of Immunology/Microbiology, Rush University, Chicago, Illinois, United States of America
| | - Kathleen M Weber
- The CORE Center, Cook County Health & Hospital System, Chicago, Illinois, United States of America
| | - Mardge Cohen
- The CORE Center, Cook County Health & Hospital System, Chicago, Illinois, United States of America
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gregory T Spear
- Department of Immunology/Microbiology, Rush University, Chicago, Illinois, United States of America
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189
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Sharabi K, Tavares CDJ, Rines AK, Puigserver P. Molecular pathophysiology of hepatic glucose production. Mol Aspects Med 2015; 46:21-33. [PMID: 26549348 DOI: 10.1016/j.mam.2015.09.003] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 12/23/2022]
Abstract
Maintaining blood glucose concentration within a relatively narrow range through periods of fasting or excess nutrient availability is essential to the survival of the organism. This is achieved through an intricate balance between glucose uptake and endogenous glucose production to maintain constant glucose concentrations. The liver plays a major role in maintaining normal whole body glucose levels by regulating the processes of de novo glucose production (gluconeogenesis) and glycogen breakdown (glycogenolysis), thus controlling the levels of hepatic glucose release. Aberrant regulation of hepatic glucose production (HGP) can result in deleterious clinical outcomes, and excessive HGP is a major contributor to the hyperglycemia observed in Type 2 diabetes mellitus (T2DM). Indeed, adjusting glycemia as close as possible to a non-diabetic range is the foremost objective in the medical treatment of patients with T2DM and is currently achieved in the clinic primarily through suppression of HGP. Here, we review the molecular mechanisms controlling HGP in response to nutritional and hormonal signals and discuss how these signals are altered in T2DM.
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Affiliation(s)
- Kfir Sharabi
- Department of Cancer Biology, Department of Cell Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Clint D J Tavares
- Department of Cancer Biology, Department of Cell Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Amy K Rines
- Department of Cancer Biology, Department of Cell Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Pere Puigserver
- Department of Cancer Biology, Department of Cell Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
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190
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Role of glycogen phosphorylase in liver glycogen metabolism. Mol Aspects Med 2015; 46:34-45. [PMID: 26519772 DOI: 10.1016/j.mam.2015.09.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 02/05/2023]
Abstract
Liver glycogen is synthesized after a meal in response to an increase in blood glucose concentration in the portal vein and endocrine and neuroendocrine signals, and is degraded to glucose between meals to maintain blood glucose homeostasis. Glycogen degradation and synthesis during the diurnal cycle are mediated by changes in the activities of phosphorylase and glycogen synthase. Phosphorylase is regulated by phosphorylation of serine-14. Only the phosphorylated form of liver phosphorylase (GPa) is catalytically active. Interconversion between GPa and GPb (unphosphorylated) is dependent on the activities of phosphorylase kinase and of phosphorylase phosphatase. The latter comprises protein phosphatase-1 in conjunction with a glycogen-targeting protein (G-subunit) of the PPP1R3 family. At least two of six G-subunits (GL and PTG) expressed in liver are involved in GPa dephosphorylation. GPa to GPb interconversion is dependent on the conformational state of phosphorylase which can be relaxed (R) or tense (T) depending on the concentrations of allosteric effectors such as glucose, glucose 6-phosphate and adenine nucleotides and on the acetylation state of lysine residues. The G-subunit, GL, encoded by PPP1R3B gene is expressed at high levels in liver and can function as a phosphorylase phosphatase and a synthase phosphatase and has an allosteric binding site for GPa at the C-terminus which inhibits synthase phosphatase activity. GPa to GPb conversion is a major upstream event in the regulation of glycogen synthesis by glucose, its downstream metabolites and extracellular signals such as insulin and neurotransmitters.
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191
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Kim OK, Nam DE, Jun W, Lee J. Cudrania tricuspidata water extract improved obesity-induced hepatic insulin resistance in db/db mice by suppressing ER stress and inflammation. Food Nutr Res 2015; 59:29165. [PMID: 26507490 PMCID: PMC4623289 DOI: 10.3402/fnr.v59.29165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/04/2015] [Accepted: 10/05/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Obesity can play a role in the development of hepatic insulin resistance. Although the molecular mechanism of the association between obesity and hepatic insulin resistance is unclear, it has been reported that obesity leads to hepatic endoplasmic reticulum (ER) stress and inflammation, which can induce the development of insulin resistance in several tissues. OBJECTIVE In this study, we investigated the associations between hepatic insulin resistance, ER, and inflammation in obesity and the effect of water extract from Cudrania tricuspidata leaves (CTL) on hepatic insulin resistance induced by ER stress and inflammation in db/db mice. DESIGN The mice were randomly divided into four groups: a normal control group (C57BL/6J), a control group (C57BL/6J-db/db), a CTL 100 group (C57BL/6J-db/db mice fed a dietary supplement of 100 mg/kg of CTL), and a CTL 300 group (C57BL/6J-db/db mice fed a dietary supplement of 300 mg/kg of CTL). After 8 weeks, we performed an oral glucose tolerance test and the mice were sacrificed. RESULTS The C57BL/6J-db/db mice developed obesity and hyperglycemia, and the ER stress response and inflammation were activated in their livers. Interestingly, there was a marked decrease in the activation of the ER stress response and insulin resistance in the livers of the C57BL/6J-db/db mice treated with CTL due to decreases in the phosphorylation of eIF2α, IRE1α, and IRS-1 serine and decreases in the mRNA expression of ATF4, c-Jun N-terminal kinase, C/EBPα, and C/EBP homologous protein. Dietary supplementation with CTL also induced a statistically significant decrease in the expression of pro-inflammatory cytokines, C-reactive protein (CRP), and NF-κB phosphorylation. CONCLUSIONS Overall, these results suggest that CTL can improve hepatic insulin resistance and hyperglycemia by controlling obesity-induced ER stress and inflammation in the liver and that CTL may be a useful agent in treating hyperglycemia.
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Affiliation(s)
- Ok-Kyung Kim
- Department of Medical Nutrition, Graduate School of East-West Science, Kyung Hee University, Yongin, Republic of Korea
| | - Da-Eun Nam
- Department of Medical Nutrition, Graduate School of East-West Science, Kyung Hee University, Yongin, Republic of Korea
| | - Woojin Jun
- Division of Food and Nutrition, Chonnam National University, Gwangju, Republic of Korea
| | - Jeongmin Lee
- Department of Medical Nutrition, Graduate School of East-West Science, Kyung Hee University, Yongin, Republic of Korea;
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192
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Behl T, Kotwani A. Possible role of endostatin in the antiangiogenic therapy of diabetic retinopathy. Life Sci 2015; 135:131-7. [DOI: 10.1016/j.lfs.2015.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/15/2015] [Accepted: 06/03/2015] [Indexed: 02/03/2023]
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193
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Kong XY, Kase ET, Herskedal A, Schjalm C, Damme M, Nesset CK, Thoresen GH, Rustan AC, Eskild W. Lack of the Lysosomal Membrane Protein, GLMP, in Mice Results in Metabolic Dysregulation in Liver. PLoS One 2015; 10:e0129402. [PMID: 26047317 PMCID: PMC4457871 DOI: 10.1371/journal.pone.0129402] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/07/2015] [Indexed: 12/25/2022] Open
Abstract
Ablation of glycosylated lysosomal membrane protein (GLMP, formerly known as NCU-G1) has been shown to cause chronic liver injury which progresses into liver fibrosis in mice. Both lysosomal dysfunction and chronic liver injury can cause metabolic dysregulation. Glmpgt/gt mice (formerly known as Ncu-g1gt/gtmice) were studied between 3 weeks and 9 months of age. Body weight gain and feed efficiency of Glmpgt/gt mice were comparable to wild type siblings, only at the age of 9 months the Glmpgt/gt siblings had significantly reduced body weight. Reduced size of epididymal fat pads was accompanied by hepatosplenomegaly in Glmpgt/gt mice. Blood analysis revealed reduced levels of blood glucose, circulating triacylglycerol and non-esterified fatty acids in Glmpgt/gt mice. Increased flux of glucose, increased de novo lipogenesis and lipid accumulation were detected in Glmpgt/gt primary hepatocytes, as well as elevated triacylglycerol levels in Glmpgt/gt liver homogenates, compared to hepatocytes and liver from wild type mice. Gene expression analysis showed an increased expression of genes involved in fatty acid uptake and lipogenesis in Glmpgt/gt liver compared to wild type. Our findings are in agreement with the metabolic alterations observed in other mouse models lacking lysosomal proteins, and with alterations characteristic for advanced chronic liver injury.
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Affiliation(s)
- Xiang Yi Kong
- Department of Bioscience, University of Oslo, Oslo, Norway
| | - Eili Tranheim Kase
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | | | | | - Markus Damme
- Institute of Biochemistry, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | | | - G. Hege Thoresen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- Department of Pharmacology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Arild C. Rustan
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Winnie Eskild
- Department of Bioscience, University of Oslo, Oslo, Norway
- * E-mail:
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194
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Miller CO, Cao J, Chekmenev E, Damon BM, Cherrington AD, Gore JC. Noninvasive measurements of glycogen in perfused mouse livers using chemical exchange saturation transfer NMR and comparison to (13)C NMR spectroscopy. Anal Chem 2015; 87:5824-30. [PMID: 25946616 PMCID: PMC4920106 DOI: 10.1021/acs.analchem.5b01296] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/06/2015] [Indexed: 02/01/2023]
Abstract
Liver glycogen represents an important physiological form of energy storage. It plays a key role in the regulation of blood glucose concentrations, and dysregulations in hepatic glycogen metabolism are linked to many diseases including diabetes and insulin resistance. In this work, we develop, optimize, and validate a noninvasive protocol to measure glycogen levels in isolated perfused mouse livers using chemical exchange saturation transfer (CEST) NMR spectroscopy. Model glycogen solutions were used to determine optimal saturation pulse parameters which were then applied to intact perfused mouse livers of varying glycogen content. Glycogen measurements from serially acquired CEST Z-spectra of livers were compared with measurements from interleaved natural abundance (13)C NMR spectra. Experimental data revealed that CEST-based glycogen measurements were highly correlated with (13)C NMR glycogen spectra. Monte Carlo simulations were then used to investigate the inherent (i.e., signal-to-noise-based) errors in the quantification of glycogen with each technique. This revealed that CEST was intrinsically more precise than (13)C NMR, although in practice may be prone to other errors induced by variations in experimental conditions. We also observed that the CEST signal from glycogen in liver was significantly less than that observed from identical amounts in solution. Our results demonstrate that CEST provides an accurate, precise, and readily accessible method to noninvasively measure liver glycogen levels and their changes. Furthermore, this technique can be used to map glycogen distributions via conventional proton magnetic resonance imaging, a capability universally available on clinical and preclinical magnetic resonance imaging (MRI) scanners vs (13)C detection, which is limited to a small fraction of clinical-scale MRI scanners.
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Affiliation(s)
- Corin O. Miller
- Merck
Research Laboratories, 2000 Galloping Hill Rd., Kenilworth, New Jersey 07033, United States
| | - Jin Cao
- Merck
Research Laboratories, 2000 Galloping Hill Rd., Kenilworth, New Jersey 07033, United States
| | - Eduard
Y. Chekmenev
- Vanderbilt
University, Institute of Imaging Science, Nashville, Tennessee 37232, United States
- Department
of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Bruce M. Damon
- Vanderbilt
University, Institute of Imaging Science, Nashville, Tennessee 37232, United States
- Department
of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department
of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Alan D. Cherrington
- Department
of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - John C. Gore
- Vanderbilt
University, Institute of Imaging Science, Nashville, Tennessee 37232, United States
- Department
of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department
of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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195
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Coate KC, Kraft G, Shiota M, Smith MS, Farmer B, Neal DW, Williams P, Cherrington AD, Moore MC. Chronic overeating impairs hepatic glucose uptake and disposition. Am J Physiol Endocrinol Metab 2015; 308:E860-7. [PMID: 25783892 PMCID: PMC4587587 DOI: 10.1152/ajpendo.00069.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/12/2015] [Indexed: 11/22/2022]
Abstract
Dogs consuming a hypercaloric high-fat and -fructose diet (52 and 17% of total energy, respectively) or a diet high in either fructose or fat for 4 wk exhibited blunted net hepatic glucose uptake (NHGU) and glycogen deposition in response to hyperinsulinemia, hyperglycemia, and portal glucose delivery. The effect of a hypercaloric diet containing neither fructose nor excessive fat has not been examined. Dogs with an initial weight of ≈25 kg consumed a chow and meat diet (31% protein, 44% carbohydrate, and 26% fat) in weight-maintaining (CTR; n = 6) or excessive (Hkcal; n = 7) amounts for 4 wk (cumulative weight gain 0.0 ± 0.3 and 1.5 ± 0.5 kg, respectively, P < 0.05). They then underwent clamp studies with infusions of somatostatin and intraportal insulin (4× basal) and glucagon (basal). The hepatic glucose load was doubled with peripheral (Pe) glucose infusion for 90 min (P1) and intraportal glucose at 4 mg·kg(-1)·min(-1) plus Pe glucose for the final 90 min (P2). NHGU was blunted (P < 0.05) in Hkcal during both periods (mg·kg(-1)·min(-1); P1: 1.7 ± 0.2 vs. 0.3 ± 0.4; P2: 3.6 ± 0.3 vs. 2.3 ± 0.4, CTR vs. Hkcal, respectively). Terminal hepatic glucokinase catalytic activity was reduced nearly 50% in Hkcal vs. CTR (P < 0.05), although glucokinase protein did not differ between groups. In Hkcal vs. CTR, liver glycogen was reduced 27% (P < 0.05), with a 91% increase in glycogen phosphorylase activity (P < 0.05) but no significant difference in glycogen synthase activity. Thus, Hkcal impaired NHGU and glycogen synthesis compared with CTR, indicating that excessive energy intake, even if the diet is balanced and nutritious, negatively impacts hepatic glucose metabolism.
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Affiliation(s)
- Katie C Coate
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Marta S Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Doss W Neal
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Phil Williams
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, Tennessee; and Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Mary Courtney Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee;
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196
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Shearer J. Methodological and metabolic considerations in the study of caffeine-containing energy drinks. Nutr Rev 2015; 72 Suppl 1:137-45. [PMID: 25293552 DOI: 10.1111/nure.12131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Caffeine-containing energy drinks are popular and widely available beverages. Despite large increases in consumption, studies documenting the nutritional, metabolic, and health implications of these beverages are limited. This review provides some important methodological considerations in the examination of these drinks and highlights their potential impact on the gastrointestinal system, liver, and metabolic health. The gastrointestinal system is important as it comes into contact with the highest concentration of energy drink ingredients and initiates a chain of events to communicate with peripheral tissues. Although energy drinks have diverse compositions, including taurine, ginseng, and carnitine, the most metabolically deleterious ingredients appear to be simple sugars (such as glucose and fructose) and caffeine. In combination, these last two ingredients have the greatest metabolic impact and potential influence on overall health.
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Affiliation(s)
- Jane Shearer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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Levina A, McLeod AI, Pulte A, Aitken JB, Lay PA. Biotransformations of Antidiabetic Vanadium Prodrugs in Mammalian Cells and Cell Culture Media: A XANES Spectroscopic Study. Inorg Chem 2015; 54:6707-18. [PMID: 25906315 PMCID: PMC4511291 DOI: 10.1021/ic5028948] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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The antidiabetic activities of vanadium(V)
and -(IV) prodrugs are determined by their ability to release active
species upon interactions with components of biological media. The
first X-ray absorption spectroscopic study of the reactivity of typical
vanadium (V) antidiabetics, vanadate ([VVO4]3–, A) and a vanadium(IV) bis(maltolato)
complex (B), with mammalian cell cultures has been performed
using HepG2 (human hepatoma), A549 (human lung carcinoma), and 3T3-L1
(mouse adipocytes and preadipocytes) cell lines, as well as the corresponding
cell culture media. X-ray absorption near-edge structure data were
analyzed using empirical correlations with a library of model vanadium(V),
-(IV), and -(III) complexes. Both A and B ([V] = 1.0 mM) gradually converged into similar mixtures of predominantly
five- and six-coordinate VV species (∼75% total
V) in a cell culture medium within 24 h at 310 K. Speciation of V
in intact HepG2 cells also changed with the incubation time (from
∼20% to ∼70% VIV of total V), but it was
largely independent of the prodrug used (A or B) or of the predominant V oxidation state in the medium. Subcellular
fractionation of A549 cells suggested that VV reduction
to VIV occurred predominantly in the cytoplasm, while accumulation
of VV in the nucleus was likely to have been facilitated
by noncovalent bonding to histone proteins. The nuclear VV is likely to modulate the transcription process and to be ultimately
related to cell death at high concentrations of V, which may be important
in anticancer activities. Mature 3T3-L1 adipocytes (unlike for preadipocytes)
showed a higher propensity to form VIV species, despite
the prevalence of VV in the medium. The distinct V biochemistry
in these cells is consistent with their crucial role in insulin-dependent
glucose and fat metabolism and may also point to an endogenous role
of V in adipocytes. The first detailed
speciation study of typical antidiabetic vanadium(V/IV) complexes
in mammalian cell culture systems showed that the complexes decomposed
rapidly in cell culture media and were further metabolized by the
cells, which included interconversions of VV and VIV species.
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Affiliation(s)
- Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Andrew I McLeod
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Anna Pulte
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jade B Aitken
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Peter A Lay
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
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198
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Kandilis AN, Papadopoulou IP, Koskinas J, Sotiropoulos G, Tiniakos DG. Liver innervation and hepatic function: new insights. J Surg Res 2015; 194:511-519. [DOI: 10.1016/j.jss.2014.12.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/04/2014] [Accepted: 12/03/2014] [Indexed: 12/14/2022]
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Raimondo A, Rees MG, Gloyn AL. Glucokinase regulatory protein: complexity at the crossroads of triglyceride and glucose metabolism. Curr Opin Lipidol 2015; 26:88-95. [PMID: 25692341 PMCID: PMC4422901 DOI: 10.1097/mol.0000000000000155] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
PURPOSE OF REVIEW Glucokinase regulator (GCKR) encodes glucokinase regulatory protein (GKRP), a hepatocyte-specific inhibitor of the glucose-metabolizing enzyme glucokinase (GCK). Genome-wide association studies have identified a common coding variant within GCKR associated with multiple metabolic traits. This review focuses on recent insights into the critical role of GKRP in hepatic glucose metabolism that have stemmed from the study of human genetics. This knowledge has improved our understanding of glucose and lipid physiology and informed the development of targeted molecular therapeutics for diabetes. RECENT FINDINGS Rare GCKR variants have effects on GKRP expression, localization, and activity. These variants are collectively associated with hypertriglyceridaemia but are not causal. Crystal structures of GKRP and the GCK-GKRP complex have been solved, providing greater insight into the molecular interactions between these proteins. Finally, small molecules have been identified that directly bind GKRP and reduce blood glucose levels in rodent models of diabetes. SUMMARY GCKR variants across the allelic spectrum have effects on glucose and lipid homeostasis. Functional analysis has highlighted numerous molecular mechanisms for GKRP dysfunction. Hepatocyte-specific GCK activation via small molecule GKRP inhibition may be a new avenue for type 2 diabetes treatment, particularly considering evidence indicating GKRP loss-of-function alone does not cause hypertriglyceridaemia.
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Affiliation(s)
- Anne Raimondo
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Matthew G. Rees
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, USA
- Howard Hughes Medical Institute, Broad Institute, Cambridge, Massachusetts, USA
| | - Anna L. Gloyn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, ORH Trust, OCDEM, Churchill Hospital, Oxford, UK
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Abstract
OBJECTIVES The placental transfer of nutrients is influenced by maternal metabolic state, placenta function and fetal demands. Human in vivo studies of this interplay are scarce and challenging. We aimed to establish a method to study placental nutrient transfer in humans. Focusing on glucose, we tested a hypothesis that maternal glucose concentrations and uteroplacental arterio-venous difference (reflecting maternal supply) determines the fetal venous-arterial glucose difference (reflecting fetal consumption). METHODS Cross-sectional in vivo study of 40 healthy women with uncomplicated term pregnancies undergoing planned caesarean section. Glucose and insulin were measured in plasma from maternal and fetal sides of the placenta, at the incoming (radial artery and umbilical vein) and outgoing vessels (uterine vein and umbilical artery). RESULTS There were significant mean (SD) uteroplacental arterio-venous 0.29 (0.23) mmol/L and fetal venous-arterial 0.38 (0.31) mmol/L glucose differences. The transplacental maternal-fetal glucose gradient was 1.22 (0.42) mmol/L. The maternal arterial glucose concentration was correlated to the fetal venous glucose concentration (r = 0.86, p<0.001), but not to the fetal venous-arterial glucose difference. The uteroplacental arterio-venous glucose difference was neither correlated to the level of glucose in the umbilical vein, nor fetal venous-arterial glucose difference. The maternal-fetal gradient was correlated to fetal venous-arterial glucose difference (r = 0.8, p<0.001) and the glucose concentration in the umbilical artery (r = -0.45, p = 0.004). Glucose and insulin concentrations were correlated in the mother (r = 0.52, p = 0.001), but not significantly in the fetus. We found no significant correlation between maternal and fetal insulin values. CONCLUSIONS We did not find a relation between indicators of maternal glucose supply and the fetal venous-arterial glucose difference. Our findings indicate that the maternal-fetal glucose gradient is significantly influenced by the fetal venous-arterial difference and not merely dependent on maternal glucose concentration or the arterio-venous difference on the maternal side of the placenta.
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