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Fordham TM, Morelli NS, Garcia-Reyes Y, Ware MA, Rahat H, Sundararajan D, Fuller KNZ, Severn C, Pyle L, Malloy CR, Jin ES, Parks EJ, Wolfe RR, Cree MG. Metabolic effects of an essential amino acid supplement in adolescents with PCOS and obesity. Obesity (Silver Spring) 2024; 32:678-690. [PMID: 38439205 DOI: 10.1002/oby.23988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 03/06/2024]
Abstract
OBJECTIVE Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, insulin resistance, and hepatic steatosis (HS). Because dietary essential amino acid (EAA) supplementation has been shown to decrease HS in various populations, this study's objective was to determine whether supplementation would decrease HS in PCOS. METHODS A randomized, double-blind, crossover, placebo-controlled trial was conducted in 21 adolescents with PCOS (BMI 37.3 ± 6.5 kg/m2, age 15.6 ± 1.3 years). Liver fat, very low-density lipoprotein (VLDL) lipogenesis, and triacylglycerol (TG) metabolism were measured following each 28-day phase of placebo or EAA. RESULTS Compared to placebo, EAA was associated with no difference in body weight (p = 0.673). Two markers of liver health improved: HS was lower (-0.8% absolute, -7.5% relative reduction, p = 0.013), as was plasma aspartate aminotransferase (AST) (-8%, p = 0.004). Plasma TG (-9%, p = 0.015) and VLDL-TG (-21%, p = 0.031) were reduced as well. VLDL-TG palmitate derived from lipogenesis was not different between the phases, nor was insulin sensitivity (p > 0.400 for both). Surprisingly, during the EAA phase, participants reported consuming fewer carbohydrates (p = 0.038) and total sugars (p = 0.046). CONCLUSIONS Similar to studies in older adults, short-term EAA supplementation in adolescents resulted in significantly lower liver fat, AST, and plasma lipids and thus may prove to be an effective treatment in this population. Additional research is needed to elucidate the mechanisms for these effects.
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Affiliation(s)
- Talyia M Fordham
- Department of Nutrition and Exercise Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Nazeen S Morelli
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Yesenia Garcia-Reyes
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Meredith A Ware
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Haseeb Rahat
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Divya Sundararajan
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kelly N Z Fuller
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Cameron Severn
- Child Health Biostatistics Core, Department of Pediatrics, Section of Endocrinology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Laura Pyle
- Child Health Biostatistics Core, Department of Pediatrics, Section of Endocrinology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, Colorado, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- VA North Texas Health Care System, Dallas, Texas, USA
| | - Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Robert R Wolfe
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Melanie G Cree
- Department of Pediatrics, Section on Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Center for Women's Health Research, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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2
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Jin ES, Malloy CR, Sharma G, Finn E, Fuller KNZ, Reyes YG, Lovell MA, Derderian SC, Schoen JA, Inge TH, Cree MG. Glycerol as a precursor for hepatic de novo glutathione synthesis in human liver. Redox Biol 2023; 63:102749. [PMID: 37224695 PMCID: PMC10225920 DOI: 10.1016/j.redox.2023.102749] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/10/2023] [Accepted: 05/14/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Glycerol is a substrate for gluconeogenesis and fatty acid esterification in the liver, processes which are upregulated in obesity and may contribute to excess fat accumulation. Glycine and glutamate, in addition to cysteine, are components of glutathione, the major antioxidant in the liver. In principle, glycerol could be incorporated into glutathione via the TCA cycle or 3-phosphoglycerate, but it is unknown whether glycerol contributes to hepatic de novo glutathione biosynthesis. METHODS Glycerol metabolism to hepatic metabolic products including glutathione was examined in the liver from adolescents undergoing bariatric surgery. Participants received oral [U-13C3]glycerol (50 mg/kg) prior to surgery and liver tissue (0.2-0.7g) was obtained during surgery. Glutathione, amino acids, and other water-soluble metabolites were extracted from the liver tissue and isotopomers were quantified with nuclear magnetic resonance spectroscopy. RESULTS Data were collected from 8 participants (2 male, 6 female; age 17.1 years [range 14-19]; BMI 47.4 kg/m2 [range 41.3-63.3]). The concentrations of free glutamate, cysteine, and glycine were similar among participants, and so were the fractions of 13C-labeled glutamate and glycine derived from [U-13C3]glycerol. The signals from all component amino acids of glutathione - glutamate, cysteine and glycine - were strong and analyzed to obtain the relative concentrations of the antioxidant in the liver. The signals from glutathione containing [13C2]glycine or [13C2]glutamate derived from the [U-13C3]glycerol drink were readily detected, and 13C-labelling patterns in the moieties were consistent with the patterns in corresponding free amino acids from the de novo glutathione synthesis pathway. The newly synthesized glutathione with [U-13C3]glycerol trended to be lower in obese adolescents with liver pathology. CONCLUSIONS This is the first report of glycerol incorporation into glutathione through glycine or glutamate metabolism in human liver. This could represent a compensatory mechanism to increase glutathione in the setting of excess glycerol delivery to the liver.
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Affiliation(s)
- Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA; VA North Texas Health Care System, Dallas, TX, 75216, USA
| | - Gaurav Sharma
- Department of Cardiovascular & Thoracic Surgery, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA; VA North Texas Health Care System, Dallas, TX, 75216, USA
| | - Erin Finn
- Department of Pediatrics, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA; Children's Hospital of Colorado, Aurora, CO, 80045, USA
| | - Kelly N Z Fuller
- Department of Pediatrics, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA; Children's Hospital of Colorado, Aurora, CO, 80045, USA
| | - Yesenia Garcia Reyes
- Department of Pediatrics, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA; Children's Hospital of Colorado, Aurora, CO, 80045, USA
| | - Mark A Lovell
- Children's Hospital of Colorado, Aurora, CO, 80045, USA; Department of Pathology, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Sarkis C Derderian
- Children's Hospital of Colorado, Aurora, CO, 80045, USA; Department of Surgery, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Jonathan A Schoen
- Children's Hospital of Colorado, Aurora, CO, 80045, USA; Department of Surgery, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Thomas H Inge
- Children's Hospital of Colorado, Aurora, CO, 80045, USA; Department of Surgery, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA; Ann and Robert Lurie Children's Hospital of Chicago, USA
| | - Melanie G Cree
- Department of Pediatrics, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, 80045, USA; Children's Hospital of Colorado, Aurora, CO, 80045, USA.
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Malloy CR, Sherry AD, Alger JR, Jin ES. Recent progress in analysis of intermediary metabolism by ex vivo 13 C NMR. NMR IN BIOMEDICINE 2023; 36:e4817. [PMID: 35997012 DOI: 10.1002/nbm.4817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/03/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Advanced imaging technologies, large-scale metabolomics, and the measurement of gene transcripts or enzyme expression all enable investigations of intermediary metabolism in human patients. Complementary information about fluxes in individual metabolic pathways may be obtained by ex vivo 13 C NMR of blood or tissue biopsies. Simple molecules such as 13 C-labeled glucose are readily administered to patients prior to surgical biopsies, and 13 C-labeled glycerol is easily administered orally to outpatients. Here, we review recent progress in practical applications of 13 C NMR to study cancer biology, the response to oxidative stress, gluconeogenesis, triglyceride synthesis in patients, as well as new insights into compartmentation of metabolism in the cytosol. The technical aspects of obtaining the sample, preparing material for analysis, and acquiring the spectra are relatively simple. This approach enables convenient, valuable, and quantitative insights into intermediary metabolism in patients.
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Affiliation(s)
- Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Veterans Affairs North Texas Healthcare System, Dallas, Texas, USA
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas, USA
| | - Jeffry R Alger
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Neurology, Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Viegas I, Di Nunzio G, Belew GD, Torres AN, Silva JG, Perpétuo L, Barosa C, Tavares LC, Jones JG. Integration of Liver Glycogen and Triglyceride NMR Isotopomer Analyses Provides a Comprehensive Coverage of Hepatic Glucose and Fructose Metabolism. Metabolites 2022; 12:1142. [PMID: 36422282 PMCID: PMC9698123 DOI: 10.3390/metabo12111142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 10/18/2023] Open
Abstract
Dietary glucose and fructose are both efficiently assimilated by the liver but a comprehensive measurement of this process starting from their conversion to sugar phosphates, involvement of the pentose phosphate pathway (PPP), and conversion to glycogen and lipid storage products, remains incomplete. Mice were fed a chow diet supplemented with 35 g/100 mL drinking water of a 55/45 fructose/glucose mixture for 18 weeks. On the final night, the sugar mixture was enriched with either [U-13C]glucose or [U-13C]fructose, and deuterated water (2H2O) was also administered. 13C-isotopomers representing newly synthesized hepatic glucose-6-phosphate (glucose-6-P), glycerol-3-phosphate, and lipogenic acetyl-CoA were quantified by 2H and 13C NMR analysis of post-mortem liver glycogen and triglyceride. These data were applied to a metabolic model covering glucose-6-P, PPP, triose-P, and de novo lipogenesis (DNL) fluxes. The glucose supplement was converted to glucose-6-P via the direct pathway, while the fructose supplement was metabolized by the liver to gluconeogenic triose-P via fructokinase-aldolase-triokinase. Glucose-6-P from all carbohydrate sources accounted for 40-60% of lipogenic acetyl-CoA and 10-12% was oxidized by the pentose phosphate pathway (PPP). The yield of NADPH from PPP flux accounted for a minority (~30%) of the total DNL requirement. In conclusion, this approach integrates measurements of glucose-6-P, PPP, and DNL fluxes to provide a holistic and informative assessment of hepatic glucose and fructose metabolism.
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Affiliation(s)
- Ivan Viegas
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Giada Di Nunzio
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Getachew D. Belew
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
- Biotechnology Department, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia
| | - Alejandra N. Torres
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - João G. Silva
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Luis Perpétuo
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
- iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Cristina Barosa
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Ludgero C. Tavares
- CIVG—Vasco da Gama Research Center, University School Vasco da Gama—EUVG, 3020-210 Coimbra, Portugal
| | - John G. Jones
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
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Shah A, Wang Y, Wondisford FE. Differential Metabolism of Glycerol Based on Oral versus Intravenous Administration in Humans. Metabolites 2022; 12:metabo12100890. [PMID: 36295792 PMCID: PMC9611849 DOI: 10.3390/metabo12100890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Glycerol can be metabolized to glucose via gluconeogenesis or lactate via glycolysis. It is unknown if glycerol is metabolized similarly in the portal and systemic circulations in humans. Eight metabolically healthy overnight-fasted individuals received equimolar amounts of 13C3-glycerol orally and intravenously on two separate occasions with serial blood draws over four hours. Serum samples underwent liquid chromatography–mass spectrometry analysis. Oral 13C3-glycerol administration led to higher average serum glucose enrichment than intravenous administration (5.02 ± 1.43 versus 4.07 ± 0.79%, p = 0.009). In contrast, intravenous 13C3-glycerol administration yielded higher average serum lactate enrichment than oral administration (5.67 ± 0.80 versus 4.85 ± 1.30%, p = 0.032). Peak serum glucose enrichment was also higher with oral administration (9.37 ± 2.93 versus 7.12 ± 1.28%, p = 0.010). Glycerol metabolism across the portal and systemic circulations is not congruent. Orally administered labeled glycerol led to greater labeled glucose production, while intravenously administration yielded greater lactate production. These data support direct glycerol to lactate conversion in humans.
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Affiliation(s)
- Ankit Shah
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Yujue Wang
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA
| | - Fredric E. Wondisford
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
- Correspondence:
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Lee MH, Neeland IJ, de Albuquerque Rocha N, Hughes C, Malloy CR, Jin ES. A randomized clinical trial evaluating the effect of empagliflozin on triglycerides in obese adults: Role of visceral fat. Metabol Open 2022; 13:100161. [PMID: 35024596 PMCID: PMC8728102 DOI: 10.1016/j.metop.2021.100161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 01/10/2023] Open
Abstract
Background Empagliflozin, a sodium glucose cotransporter 2 inhibitor, is a medication to treat type 2 diabetes. The effect of empagliflozin in persons without diabetes has received less attention. Here we conducted a randomized, double-blind placebo-controlled clinical trial to examine the effect of empagliflozin on plasma triglycerides in obese non-diabetic adults. Methods Participants (n = 35; BMI ≥ 30 kg/m2) underwent body composition assessments using MRI, and were randomly assigned to either placebo or empagliflozin (10 mg/d) for three months. At the baseline and post-treatment visit, after an overnight fast, blood was drawn for biochemical analysis. Participants received [U–13C3]glycerol orally followed by multiple blood draws over 3 h to examine glycerol incorporation into triglycerides using NMR spectroscopy. Results The changes in blood triglyceride concentration with empagliflozin therapy related to the mass of baseline visceral adipose tissue (VAT; r = 0.53, p = 0.04). Empagliflozin slightly lowered triglycerides in obese subjects with low VAT, but increased triglycerides in the subjects with high VAT. Consistently, empagliflozin effectively suppressed triglyceride synthesis following [U–13C3]glycerol administration in the subjects with low VAT (p < 0.05), but not in the subjects with high VAT. The subjects with high VAT lost body weight after three months of empagliflozin treatment. In all subjects, about 20% of the triglyceride backbone originated from mitochondrial metabolism of glycerol. Conclusions The effect of empagliflozin on triglycerides in obese adults differed depending on VAT. Empagliflozin suppressed triglyceride synthesis in the subjects with low VAT, but tended to increase triglycerides in those with high VAT. Visceral fat modulates the effect of empagliflozin on triglycerides in obese adults. Empagliflozin suppresses triglyceride synthesis in obese adults with low visceral fat. Empagliflozin tends to increase triglycerides in obese adults with high visceral fat. Empagliflozin induces weight loss in obese adults with high visceral fat.
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Affiliation(s)
- Min Hee Lee
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ian J. Neeland
- Department of Medicine, University Hospitals Cleveland Medical Center and Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | | | - Connor Hughes
- Department of Internal Medicine, University of Texas Southwestern Medical Center, USA
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, USA
- Department of Radiology, University of Texas Southwestern Medical Center, USA
- VA North Texas Health Care System, Dallas, TX, 75216, USA
| | - Eunsook S. Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, USA
- Corresponding author. Advanced Imaging Research Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-8568, USA.
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Cheng Y, Gan-Schreier H, Seeßle J, Staffer S, Tuma-Kellner S, Khnykin D, Stremmel W, Merle U, Herrmann T, Chamulitrat W. Methionine- and Choline-Deficient Diet Enhances Adipose Lipolysis and Leptin Release in aP2-Cre Fatp4-Knockout Mice. Mol Nutr Food Res 2020; 64:e2000361. [PMID: 32991778 DOI: 10.1002/mnfr.202000361] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/22/2020] [Indexed: 12/11/2022]
Abstract
SCOPE Inadequate intake of choline commonly leads to liver diseases. Methionine- and choline-deficient diets (MCDD) induce fatty liver in mice which is partly mediated by triglyceride (TG) lipolysis in white adipose tissues (WATs). Because Fatp4 knockdown has been shown to increase adipocyte lipolysis in vitro, here, the effects of MCDD on WAT lipolysis in aP2-Cre Fatp4-knockout (Fatp4A-/- ) mice are determined. METHODS AND RESULTS Isolated WATs of Fatp4A-/- mice exposed to MCD medium show an increase in lipolysis, and the strongest effect is noted on glycerol release from subcutaneous fat. Fatp4A-/- mice fed with MCDD for 4 weeks show an increase in serum glycerol, TG, and leptin levels associated with the activation of hormone-sensitive lipase in subcutaneous fat. Chow-fed Fatp4A-/- mice also show an increase in serum leptin and very-low-density lipoproteins as well as liver phosphatidylcholine and sphingomyelin levels. Both chow- and MCDD-fed Fatp4A-/- mice show a decrease in serum ketone and WAT sphingomyelin levels which supports a metabolic shift to TG for subsequent WAT lipolysis CONCLUSIONS: Adipose Fatp4 deficiency leads to TG lipolysis and leptin release, which are exaggerated by MCDD. The data imply hyperlipidemia risk by a low dietary choline intake and gene mutations that increase adipose TG levels.
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Affiliation(s)
- Yuting Cheng
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Hongying Gan-Schreier
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Jessica Seeßle
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Simone Staffer
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Denis Khnykin
- Department of Pathology and Center for Immune Regulation, Rikshospitalet University Hospital, 0424, Oslo, Norway
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Uta Merle
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Thomas Herrmann
- Westkuesten Hospital, Esmarchstraße 50, 25746, Heide, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
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8
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Belew GD, Di Nunzio G, Tavares L, Silva JG, Torres AN, Jones JG. Estimating pentose phosphate pathway activity from the analysis of hepatic glycogen 13 C-isotopomers derived from [U- 13 C]fructose and [U- 13 C]glucose. Magn Reson Med 2020; 84:2765-2771. [PMID: 32301167 DOI: 10.1002/mrm.28286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/21/2020] [Accepted: 03/25/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE The pentose phosphate pathway (PPP) is an important component of hepatic intermediary metabolism. Jin et al developed an elegant 13 C-NMR method for measuring hepatic PPP flux by quantifying the distribution of glucose 13 C-isotopomers formed from [U-13 C]glycerol. We demonstrate that this approach can be extended to exogenous [U-13 C]fructose and [U-13 C]glucose precursors by 13 C-NMR analysis of glycogen. METHODS Twelve male C57BL/6 mice fed standard chow were provided a 55/45 mixture of fructose and glucose at 30% w/v in the drinking water for 18 wk. On the evening before sacrifice, the fructose component was enriched with 20% [U-13 C]fructose for 6 mice, while the glucose component was enriched with 20% [U-13 C]glucose for the remaining 6 mice. Mice were allowed to feed and drink naturally overnight, and then, euthanized. Livers were freeze-clamped and glycogen was extracted and derivatized for 13 C NMR spectroscopy. Flux of each sugar into the PPP relative to its incorporation into glycogen was quantified from selected 13 C glycogen isotopomer ratios. RESULTS Both [U-13 C]fructose and [U-13 C]glucose precursors yielded glycogen 13 C-isotopomer distributions that were characteristic of PPP activity. The fraction of [U-13 C]glucose utilized by the PPP relative to its conversion to glycogen via the direct pathway was 14 ± 1%, while that from [U-13 C]fructose relative to its conversion to glycogen via the indirect pathway was significantly lower (10 ± 1%, P = .00032). CONCLUSIONS Hepatic PPP fluxes from both [U-13 C]glucose and [U-13 C]fructose precursors were assessed by 13 C NMR analysis of glycogen 13 C-isotopomers. Glucose-6-phosphate generated via glucokinase and the direct pathway is preferentially utilized by the PPP.
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Affiliation(s)
- Getachew D Belew
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Giada Di Nunzio
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ludgero Tavares
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Joao G Silva
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Alejandra N Torres
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - John G Jones
- Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
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9
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Behn CD, Bubar K, Jin ES, Malloy CR, Parks EJ, Cree-Green M. Advances in stable isotope tracer methodology part 1: hepatic metabolism via isotopomer analysis and postprandial lipolysis modeling. J Investig Med 2020; 68:3-10. [PMID: 31554675 PMCID: PMC7372575 DOI: 10.1136/jim-2019-001109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2019] [Indexed: 01/02/2023]
Abstract
Stable isotope tracers have been used to gain an understanding of integrative animal and human physiology. More commonly studied organ systems include hepatic glucose metabolism, lipolysis from adipose tissue, and whole body protein metabolism. Recent improvements in isotope methodology have included the use of novel physiologic methods/models and mathematical modeling of data during different physiologic states. Here we review some of the latest advancements in this field and highlight future research needs. First we discuss the use of an oral [U-13C3]-glycerol tracer to determine the relative contribution of glycerol carbons to hepatic glucose production after first cycling through the tricarboxylic acid cycle, entry of glycerol into the pentose phosphate pathway or direct conversion of glycerol into the glucose. Second, we describe an adaptation of the established oral minimal model used to define postprandial glucose dynamics to include glycerol dynamics in an oral glucose tolerance test with a [2H5]-glycerol tracer to determine dynamic changes in lipolysis. Simulation results were optimized when parameters describing glycerol flux were determined with a hybrid approach using both tracer-based calculations and constrained parameter optimization. Both of these methodologies can be used to expand our knowledge of not only human physiology, but also the effects of various nutritional strategies and medications on metabolism.
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Affiliation(s)
- Cecilia Diniz Behn
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, USA
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kate Bubar
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, USA
| | - Eunsook S. Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Elizabeth J. Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA
| | - Melanie Cree-Green
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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10
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Lee MH, Malloy CR, Corbin IR, Li J, Jin ES. Assessing the pentose phosphate pathway using [2, 3- 13 C 2 ]glucose. NMR IN BIOMEDICINE 2019; 32:e4096. [PMID: 30924572 PMCID: PMC6525052 DOI: 10.1002/nbm.4096] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 05/24/2023]
Abstract
The pentose phosphate pathway (PPP) is essential for reductive biosynthesis, antioxidant processes and nucleotide production. Common tracers such as [1,2-13 C2 ]glucose rely on detection of 13 C in lactate and require assumptions to correct natural 13 C abundance. Here, we introduce a novel and specific tracer of the PPP, [2,3-13 C2 ]glucose. 13 C NMR analysis of the resulting isotopomers is informative because [1,2-13 C2 ]lactate arises from glycolysis and [2,3-13 C2 ]lactate arises exclusively through the PPP. A correction for natural abundance is unnecessary. In rats receiving [2,3-13 C2 ]glucose, the PPP was more active in the fed versus fasted state in the liver and the heart, consistent with increased expression of key enzymes in the PPP. Both the PPP and glycolysis were substantially increased in hepatoma compared with liver. In summary, [2,3-13 C2 ]glucose and 13 C NMR simplify assessment of the PPP.
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Affiliation(s)
- Min Hee Lee
- Department of Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Craig R. Malloy
- Department of Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- VA North Texas Health Care System, Dallas, TX 75216
| | - Ian R. Corbin
- Department of Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Junjie Li
- Department of Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Eunsook S. Jin
- Department of Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
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11
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Carreau AM, Jin ES, Garcia-Reyes Y, Rahat H, Nadeau KJ, Malloy CR, Cree-Green M. A simple method to monitor hepatic gluconeogenesis and triglyceride synthesis following oral sugar tolerance test in obese adolescents. Am J Physiol Regul Integr Comp Physiol 2019; 317:R134-R142. [PMID: 31042400 DOI: 10.1152/ajpregu.00047.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hepatic energy metabolism is a key element in many metabolic diseases. Hepatic anaplerosis provides carbons for gluconeogenesis (GNG) and triglyceride (TG) synthesis. We aimed to optimize a protocol that measures hepatic anaplerotic contribution for GNG, TG synthesis, and hepatic pentose phosphate pathway (PPP) activity using a single dose of oral [U-13C3]glycerol paired with an oral sugar tolerance test (OSTT) in a population with significant insulin resistance. The OSTT (75 g glucose + 25 g fructose) was administered to eight obese adolescents with polycystic ovarian syndrome (PCOS) followed by ingestion of [U-13C3]glycerol at t = 180 or t = 210 min. 13C-labeling patterns of serum glucose and TG-glycerol were determined by nuclear magnetic resonance. 13C enrichment in plasma TG-glycerol was detectable and stable from 240 to 390 min with the [U-13C3]glycerol drink at t = 180 min(3.65 ± 2.3 to 4.47 ± 1.4%; P > 0.4), but the enrichment was undetectable at 240 min with the glycerol drink at t = 210 min. The relative contribution from anaplerosis was determined at the end of the OSTT [18.5 ±3.4% (t = 180 min) vs. 16.0 ± 3.5% (t = 210 min); P = 0.27]. [U-13C3]glycerol was incorporated into GNG 390 min after the OSTT with an enrichment of 7.5-12.5%. Glucose derived from TCA cycle activity was 0.3-1%, and the PPP activity was 2.8-4.7%. In conclusion, it is possible to obtain relative measurements of hepatic anaplerotic contribution to both GNG and TG esterification following an OSTT in a highly insulin-resistant population using a minimally invasive technique. Tracer administration should be timed to allow enough de novo TG esterification and endogenous glucose release after the sugar drink.
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Affiliation(s)
- Anne-Marie Carreau
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Yesenia Garcia-Reyes
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Haseeb Rahat
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado
| | - Kristen J Nadeau
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado.,Center for Women's Health Research , Aurora, Colorado
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Melanie Cree-Green
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus , Aurora, Colorado.,Center for Women's Health Research , Aurora, Colorado
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12
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Alger JR, Sherry AD, Malloy CR. tcaSIM: A Simulation Program for Optimal Design of 13C Tracer Experiments for Analysis of Metabolic Flux by NMR and Mass Spectroscopy. ACTA ACUST UNITED AC 2019; 6:176-187. [PMID: 31745452 DOI: 10.2174/2213235x07666181219115856] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Increasingly sophisticated instrumentation for chemical separations and identification has facilitated rapid advancements in our understanding of the metabolome. Since many analyses are performed using either mass spectroscopy (MS) or nuclear magnetic resonance (NMR) spectroscopy, the spin ½ stable 13C isotope is now widely used as a metabolic tracer. There is strong interest in quantitative analysis of metabolic flux through pathways in vivo, particularly in human patients. Although instrumentation advances and scientific interests in metabolism are increasing in parallel, a practical and rational design of a 13C tracer study can be challenging. Prior to planning the details of a tracer experiment, is it important to consider whether the analytical results will be sensitive to flux through the pathways of interest. Here, we briefly summarize the various approaches that have been used to design carbon tracer experiments, outline the sources of complexity, and illustrate the use of a software tool, tcaSIM, to aid in the experimental design of both MS and NMR data in complex systems including patients.
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Affiliation(s)
- Jeffry R Alger
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,NeuroSpectroScopics LLC, Sherman Oaks, California
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Chemistry, University of Texas at Dallas, Richardson, Texas
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Veterans Affairs North Texas Healthcare System, Dallas, Texas
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13
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Jin ES, Browning JD, Murphy RE, Malloy CR. Fatty liver disrupts glycerol metabolism in gluconeogenic and lipogenic pathways in humans. J Lipid Res 2018; 59:1685-1694. [PMID: 30054343 PMCID: PMC6121920 DOI: 10.1194/jlr.m086405] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/27/2018] [Indexed: 12/29/2022] Open
Abstract
It is a challenge to assess metabolic dysregulation in fatty liver of human patients prior to clinical manifestations. Here, we recruited obese, but otherwise healthy, subjects to examine biochemical processes in the liver with simple triglyceride accumulation using stable isotopes and NMR analysis of metabolic products in blood. Intrahepatic triglycerides were measured using 1H magnetic resonance spectroscopy, and volunteers received 2H2O and [U-13C3]glycerol orally, followed by a series of blood draws. NMR analysis of plasma triglycerides and glucose provided detailed information about metabolic pathways in patients with simple hepatic steatosis. Compared with subjects with low hepatic fat, patients with hepatic steatosis were characterized by the following: lower 13C enrichments in the glycerol backbones of triglycerides (i.e., TG-[13C]glycerol), higher [U-13C3]glycerol metabolism through the tricarboxylic acid (TCA) cycle, delayed gluconeogenesis from [U-13C3]glycerol, and less flexibility in adjusting supporting fluxes of glucose production upon an oral load of glycerol. In summary, simple hepatic steatosis was associated with enhanced [U-13C3]glycerol metabolism through pathways that intersect the TCA cycle and delayed gluconeogenesis from glycerol.
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Affiliation(s)
- Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390.
| | - Jeffrey D Browning
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390; Department of Clinical Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Rebecca E Murphy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390; Veterans Affairs North Texas Health Care System, Dallas, TX 75216
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14
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Jin ES, Lee MH, Murphy RE, Malloy CR. Pentose phosphate pathway activity parallels lipogenesis but not antioxidant processes in rat liver. Am J Physiol Endocrinol Metab 2018; 314:E543-E551. [PMID: 29351478 PMCID: PMC6032064 DOI: 10.1152/ajpendo.00342.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 11/22/2022]
Abstract
The pentose phosphate pathway (PPP) is widely assumed to play a key role in both reductive biosynthesis and protection from oxidative stress because it is the major source of NADPH. However, little is known about the activity of the PPP in fatty liver, which is characterized by both oxidative stress and lipogenesis. This study was designed to test whether the PPP is active in parallel with lipogenesis and antioxidant processes in the fatty liver of whole animals. Eight- and 16-wk-old obese Zucker diabetic fatty rats and their lean littermates received [U-13C3]glycerol, and 13C labeling patterns of glucose and triglycerides were analyzed for the assessment of hepatic PPP activity and the potentially related processes simultaneously. Oxidative stress, antioxidant activity, and NADPH-producing enzymes in the liver were further examined. Both PPP activity and lipogenesis increased in the fatty liver of young obese Zucker rats but decreased together in older obese Zucker rats. As expected, lipid peroxidation measured by malondialdehyde increased in the fatty liver of obese Zucker rats at both ages. However, evidence for antioxidant processes such as [glutathione] or activities of glutathione reductase, glutathione peroxidase, and catalase was not altered. Hepatic PPP activity paralleled lipogenesis but was dissociated from biomarkers of oxidative stress or antioxidant processes. In summary, NADPH from the PPP was presumably consumed for reductive biosynthesis rather than antioxidant defense in the fatty liver.
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Affiliation(s)
- Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
- Department of Internal Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Min Hee Lee
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Rebecca E Murphy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas, Texas
- Department of Internal Medicine, University of Texas Southwestern Medical Center , Dallas, Texas
- Department of Radiology, University of Texas Southwestern Medical Center , Dallas, Texas
- Veterans Administration, North Texas Health Care System, Dallas, Texas
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15
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Grenier-Larouche T, Carreau AM, Geloën A, Frisch F, Biertho L, Marceau S, Lebel S, Hould FS, Richard D, Tchernof A, Carpentier AC. Fatty Acid Metabolic Remodeling During Type 2 Diabetes Remission After Bariatric Surgery. Diabetes 2017; 66:2743-2755. [PMID: 28835473 DOI: 10.2337/db17-0414] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 08/10/2017] [Indexed: 11/13/2022]
Abstract
Hypertrophic remodeling of white adipose tissues is associated with overexposure of lean organs to circulating triglycerides (TGs) and nonesterified fatty acids (NEFAs), ultimately leading to insulin resistance. Bariatric surgery promotes type 2 diabetes (T2D) remission through a succession of weight loss-dependent and -independent mechanisms. However, the longitudinal contribution of adipocyte size reduction and fatty acid metabolic handling remain unknown. Here we show that severely obese participants with T2D display hypertriglyceridemia and excessive systemic lipolysis during intravenous lipid overload. Three days after biliopancreatic diversion with duodenal switch (DS), whole-body glycerol turnover was normalized and associated with lower HOMA-insulin resistance index. A mean excess weight loss of 84% was achieved 12 months after DS. The smaller subcutaneous adipocyte size predicted better glycemic control in T2D. TG disposal and acylcarnitine production during lipid overload, along with muscle insulin sensitivity, improved with weight loss. Nevertheless, systemic NEFA fluxes and NEFA spillover remained similar, suggesting that increased NEFA storage capacity per volume of adipose tissue exactly compensated for the decrease in fat mass during weight loss. In conclusion, T2D remission after DS is mainly associated with greater circulating TG disposal, lower systemic lipolysis, and better fatty acid handling by lean tissues.
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Affiliation(s)
- Thomas Grenier-Larouche
- Department of Medicine, Division of Endocrinology, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Anne-Marie Carreau
- Department of Medicine, Division of Endocrinology, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Alain Geloën
- University of Lyon, CARMEN INSERM U1060, INSA-Lyon, Villeurbanne, France
| | - Frédérique Frisch
- Department of Medicine, Division of Endocrinology, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Laurent Biertho
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Simon Marceau
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Stéfane Lebel
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Frédéric-Simon Hould
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - André Tchernof
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, Québec, Canada
| | - André C Carpentier
- Department of Medicine, Division of Endocrinology, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada
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16
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Neeland IJ, Hughes C, Ayers CR, Malloy CR, Jin ES. Effects of visceral adiposity on glycerol pathways in gluconeogenesis. Metabolism 2017; 67:80-89. [PMID: 28081781 PMCID: PMC5244471 DOI: 10.1016/j.metabol.2016.11.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/27/2016] [Accepted: 11/22/2016] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To determine the feasibility of using oral 13C labeled glycerol to assess effects of visceral adiposity on gluconeogenic pathways in obese humans. RESEARCH DESIGN AND METHODS Obese (BMI ≥30kg/m2) participants without type 2 diabetes underwent visceral adipose tissue (VAT) assessment and stratification by median VAT into high VAT-fasting (n=3), low VAT-fasting (n=4), and high VAT-refed (n=2) groups. Participants ingested [U-13C3] glycerol and blood samples were subsequently analyzed at multiple time points over 3h by NMR spectroscopy. The fractions of plasma glucose (enrichment) derived from [U-13C3] glycerol via hepatic gluconeogenesis, pentose phosphate pathway (PPP), and tricarboxylic acid (TCA) cycle were assessed using 13C NMR analysis of glucose. Mixed linear models were used to compare 13C enrichment in glucose between groups. RESULTS Mean age, BMI, and baseline glucose were 49years, 40.1kg/m2, and 98mg/dl, respectively. Up to 20% of glycerol was metabolized in the TCA cycle prior to gluconeogenesis and PPP activity was minor (<1% of total glucose) in all participants. There was a 21% decrease in 13C enrichment in plasma glucose in the high VAT-fasting compared with low VAT-fasting group (p=0.03), suggesting dilution by endogenous glycerol. High VAT-refed participants had 37% less 13C enrichment in glucose compared with high VAT-fasting (p=0.02). There was a trend toward lower [1,2-13C2] (via PPP) and [5,6-13C2]/[4,5,6-13C3] (via TCA cycle) glucose in high VAT versus low VAT groups. CONCLUSIONS We applied a simple method to detect gluconeogenesis from glycerol in obese humans. Our findings provide preliminary evidence that excess visceral fat disrupts multiple pathways in hepatic gluconeogenesis from glycerol.
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Affiliation(s)
- Ian J Neeland
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Connor Hughes
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Colby R Ayers
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Craig R Malloy
- Advanced Imaging Research Center and Departments of Internal Medicine and Radiology, University of Texas Southwestern Medical Center and VA North Texas Healthcare System, Dallas, TX, USA
| | - Eunsook S Jin
- Advanced Imaging Research Center and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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