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McCue MD. CO 2 scrubbing, zero gases, Keeling plots, and a mathematical approach to ameliorate the deleterious effects of ambient CO 2 during 13 C breath testing in humans and animals. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9639. [PMID: 37817343 DOI: 10.1002/rcm.9639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/17/2023] [Accepted: 08/26/2023] [Indexed: 10/12/2023]
Abstract
13 C breath testing is increasingly used in physiology and ecology research because of what it reveals about the different fuels that animals oxidize to meet their energetic demands. Here I review the practice of 13 C breath testing in humans and other animals and describe the impact that contamination by ambient/background CO2 in the air can have on the accuracy of 13 C breath measurements. I briefly discuss physical methods to avoid sample contamination as well as the Keeling plot approach that researchers have been using for the past two decades to estimate δ13 C from breath samples mixed with ambient CO2 . Unfortunately, Keeling plots are not suited for 13 C breath testing in common situations where (1) a subject's VCO2 is dynamic, (2) ambient [CO2 ] may change, (3) a subject is sensitive to hypercapnia, or (4) in any flow-through indirect calorimetry system. As such, I present a mathematical solution that addresses these issues by using information about the instantaneous [CO2 ] and the δ13 CO2 of ambient air as well as the diluted breath sample to back-calculate the δ13 CO2 in the CO2 exhaled by the animal. I validate this approach by titrating a sample of 13 C-enriched gas into an air stream and demonstrate its ability to provide accurate values across a wide range of breath and air mixtures. This approach allows researchers to instantaneously calculate the δ13 C of exhaled gas of humans or other animals in real time without having to scrub ambient CO2 or rely on estimated values.
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Verlande A, Chun SK, Song WA, Oettler D, Knot HJ, Masri S. Exogenous detection of 13C-glucose metabolism in tumor and diet-induced obesity models. Front Physiol 2022; 13:1023614. [PMID: 36277179 PMCID: PMC9581140 DOI: 10.3389/fphys.2022.1023614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Metabolic rewiring is a hallmark feature prevalent in cancer cells as well as insulin resistance (IR) associated with diet-induced obesity (DIO). For instance, tumor metabolism shifts towards an enhanced glycolytic state even under aerobic conditions. In contrast, DIO triggers lipid-induced IR by impairing insulin signaling and reducing insulin-stimulated glucose uptake. Based on physiological differences in systemic metabolism, we used a breath analysis approach to discriminate between different pathological states using glucose oxidation as a readout. We assessed glucose utilization in lung cancer-induced cachexia and DIO mouse models using a U-13C glucose tracer and stable isotope sensors integrated into an indirect calorimetry system. Our data showed increased 13CO2 expired by tumor-bearing (TB) mice and a reduction in exhaled 13CO2 in the DIO model. Taken together, our findings illustrate high glucose uptake and consumption in TB animals and decreased glucose uptake and oxidation in obese mice with an IR phenotype. Our work has important translational implications for the utility of stable isotopes in breath-based detection of glucose homeostasis in models of lung cancer progression and DIO.
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Affiliation(s)
- Amandine Verlande
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States
| | - Sung Kook Chun
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States
| | - Wei A. Song
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States
| | | | - Harm J. Knot
- TSE Systems Inc., Chesterfield, MO, United States
| | - Selma Masri
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA, United States
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Löffler MC, Betz MJ, Blondin DP, Augustin R, Sharma AK, Tseng YH, Scheele C, Zimdahl H, Mark M, Hennige AM, Wolfrum C, Langhans W, Hamilton BS, Neubauer H. Challenges in tackling energy expenditure as obesity therapy: From preclinical models to clinical application. Mol Metab 2021; 51:101237. [PMID: 33878401 PMCID: PMC8122111 DOI: 10.1016/j.molmet.2021.101237] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/31/2021] [Accepted: 04/13/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND A chronic imbalance of energy intake and energy expenditure results in excess fat storage. The obesity often caused by this overweight is detrimental to the health of millions of people. Understanding both sides of the energy balance equation and their counter-regulatory mechanisms is critical to the development of effective therapies to treat this epidemic. SCOPE OF REVIEW Behaviors surrounding ingestion have been reviewed extensively. This review focuses more specifically on energy expenditure regarding bodyweight control, with a particular emphasis on the organs and attractive metabolic processes known to reduce bodyweight. Moreover, previous and current attempts at anti-obesity strategies focusing on energy expenditure are highlighted. Precise measurements of energy expenditure, which consist of cellular, animal, and human models, as well as measurements of their translatability, are required to provide the most effective therapies. MAJOR CONCLUSIONS A precise understanding of the components surrounding energy expenditure, including tailored approaches based on genetic, biomarker, or physical characteristics, must be integrated into future anti-obesity treatments. Further comprehensive investigations are required to define suitable treatments, especially because the complex nature of the human perspective remains poorly understood.
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Affiliation(s)
- Mona C Löffler
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany
| | - Matthias J Betz
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
| | - Denis P Blondin
- Department of Medicine, Division of Neurology, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, QC, Canada
| | - Robert Augustin
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany
| | - Anand K Sharma
- Institute of Food, Nutrition and Health, ETH Zürich, Schwerzenbach, Switzerland
| | - Yu-Hua Tseng
- Joslin Diabetes Center, Section on Integrative Physiology and Metabolism, Harvard Medical School, Boston, MA, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Camilla Scheele
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Denmark
| | - Heike Zimdahl
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany
| | - Michael Mark
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany
| | - Anita M Hennige
- Therapeutic Area CardioMetabolism & Respiratory, Boehringer Ingelheim International GmbH, Biberach, Germany
| | - Christian Wolfrum
- Institute of Food, Nutrition and Health, ETH Zürich, Schwerzenbach, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Department of Health Sciences and Technology, ETH Zürich, Switzerland
| | - Bradford S Hamilton
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany
| | - Heike Neubauer
- Cardio Metabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany.
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Hageman JH, Erdõs B, Keijer J, Adriaens M, de Wit B, Stañková B, Tvrzická E, Arts IC, Nieuwenhuizen AG. The Effect of Partly Replacing Vegetable Fat with Bovine Milk Fat in Infant Formula on Postprandial Lipid and Energy Metabolism: A Proof-of-principle Study in Healthy Young Male Adults. Mol Nutr Food Res 2021; 65:e2000848. [PMID: 33682997 PMCID: PMC8243939 DOI: 10.1002/mnfr.202000848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/21/2020] [Indexed: 11/10/2022]
Abstract
SCOPE Infant formula (IF) uses besides vegetable fats also bovine milk fat, which differs in triacylglycerol (TAG) structure. Furthermore, it differs in fatty acid (FA) composition. Whether changing fat source in IF affects postprandial energy metabolism, lipemic response, and blood lipid profile is unknown. METHODS AND RESULTS A proof-of-principle study, with a randomized controlled double-blind cross-over design, is conducted. Twenty healthy male adults consumed drinks with either 100% vegetable fat (VEG) or 67% bovine milk fat and 33% vegetable fat (BOV), on 2 separate days. For a detailed insight in the postprandial responses, indirect calorimetry is performed continuously, and venous blood samples are taken every 30 min, until 5 h postprandially. No differences in postprandial energy metabolism, serum lipids, lipoprotein, or chylomicron concentrations are observed between drinks. After consumption of VEG-drink, C18:2n-6 in serum increased. Observed differences in chylomicron FA profile reflect differences in initial FA profile of test drinks. Serum ketone bodies concentrations increase following consumption of BOV-drink. CONCLUSIONS The use of bovine milk fat in IF does neither affect postprandial energy metabolism nor lipemic response in healthy adults, but alters postprandial FA profiles and ketone metabolism. Whether the exact same effects occur in infants requires experimental verification.
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Affiliation(s)
- Jeske H.J. Hageman
- Human and Animal PhysiologyWageningen Universityde Elst 1Wageningen6708 WDNetherlands
- FrieslandCampinaStationsplein 1Amersfoort3818 LENetherlands
| | - Balázs Erdõs
- Maastricht Centre for Systems Biology (MaCSBio)Maastricht UniversityMaastricht6200 MDNetherlands
| | - Jaap Keijer
- Human and Animal PhysiologyWageningen Universityde Elst 1Wageningen6708 WDNetherlands
| | - Michiel Adriaens
- Maastricht Centre for Systems Biology (MaCSBio)Maastricht UniversityMaastricht6200 MDNetherlands
| | - Britt de Wit
- Human and Animal PhysiologyWageningen Universityde Elst 1Wageningen6708 WDNetherlands
| | - Barbora Stañková
- 4th Department of Internal Medicine1st Faculty of MedicineCharles UniversityPragueCzech Republic
| | - Eva Tvrzická
- 4th Department of Internal Medicine1st Faculty of MedicineCharles UniversityPragueCzech Republic
| | - Ilja C.W. Arts
- Maastricht Centre for Systems Biology (MaCSBio)Maastricht UniversityMaastricht6200 MDNetherlands
| | - Arie G. Nieuwenhuizen
- Human and Animal PhysiologyWageningen Universityde Elst 1Wageningen6708 WDNetherlands
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Williams HC, Piron MA, Nation GK, Walsh AE, Young LEA, Sun RC, Johnson LA. Oral Gavage Delivery of Stable Isotope Tracer for In Vivo Metabolomics. Metabolites 2020; 10:E501. [PMID: 33302448 PMCID: PMC7764755 DOI: 10.3390/metabo10120501] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/16/2022] Open
Abstract
Stable isotope-resolved metabolomics (SIRM) is a powerful tool for understanding disease. Advances in SIRM techniques have improved isotopic delivery and expanded the workflow from exclusively in vitro applications to in vivo methodologies to study systemic metabolism. Here, we report a simple, minimally-invasive and cost-effective method of tracer delivery to study SIRM in vivo in laboratory mice. Following a brief fasting period, we orally administered a solution of [U-13C] glucose through a blunt gavage needle without anesthesia, at a physiological dose commonly used for glucose tolerance tests (2 g/kg bodyweight). We defined isotopic enrichment in plasma and tissue at 15, 30, 120, and 240 min post-gavage. 13C-labeled glucose peaked in plasma around 15 min post-gavage, followed by period of metabolic decay and clearance until 4 h. We demonstrate robust enrichment of a variety of central carbon metabolites in the plasma, brain and liver of C57/BL6 mice, including amino acids, neurotransmitters, and glycolytic and tricarboxylic acid (TCA) cycle intermediates. We then applied this method to study in vivo metabolism in two distinct mouse models of diseases known to involve dysregulation of glucose metabolism: Alzheimer's disease and type II diabetes. By delivering [U-13C] glucose via oral gavage to the 5XFAD Alzheimer's disease model and the Lepob/ob type II diabetes model, we were able to resolve significant differences in multiple central carbon pathways in both model systems, thus providing evidence of the utility of this method to study diseases with metabolic components. Together, these data clearly demonstrate the efficacy and efficiency of an oral gavage delivery method, and present a clear time course for 13C enrichment in plasma, liver and brain of mice following oral gavage of [U-13C] glucose-data we hope will aid other researchers in their own 13C-glucose metabolomics study design.
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Affiliation(s)
- Holden C. Williams
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; (H.C.W.); (M.A.P.); (G.K.N.); (A.E.W.)
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Margaret A. Piron
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; (H.C.W.); (M.A.P.); (G.K.N.); (A.E.W.)
| | - Grant K. Nation
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; (H.C.W.); (M.A.P.); (G.K.N.); (A.E.W.)
| | - Adeline E. Walsh
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; (H.C.W.); (M.A.P.); (G.K.N.); (A.E.W.)
| | - Lyndsay E. A. Young
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536, USA;
| | - Ramon C. Sun
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY 40536, USA
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Lance A. Johnson
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; (H.C.W.); (M.A.P.); (G.K.N.); (A.E.W.)
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Kim IY, Park S, Kim Y, Chang Y, Choi CS, Suh SH, Wolfe RR. In Vivo and In Vitro Quantification of Glucose Kinetics: From Bedside to Bench. Endocrinol Metab (Seoul) 2020; 35:733-749. [PMID: 33397035 PMCID: PMC7803595 DOI: 10.3803/enm.2020.406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 11/27/2020] [Indexed: 12/16/2022] Open
Abstract
Like other substrates, plasma glucose is in a dynamic state of constant turnover (i.e., rates of glucose appearance [Ra glucose] into and disappearance [Rd glucose] from the plasma) while staying within a narrow range of normal concentrations, a physiological priority. Persistent imbalance of glucose turnover leads to elevations (i.e., hyperglycemia, Ra>Rd) or falls (i.e., hypoglycemia, Ra<Rd) in the pool size, leading to clinical conditions such as diabetes. Endogenous Ra glucose is divided into hepatic glucose production via glycogenolysis and gluconeogenesis (GNG) and renal GNG. On the other hand, Rd glucose, the summed rate of glucose uptake by tissues/organs, involves various intracellular metabolic pathways including glycolysis, the tricarboxylic acid (TCA) cycle, and oxidation at varying rates depending on the metabolic status. Despite the dynamic nature of glucose metabolism, metabolic studies typically rely on measurements of static, snapshot information such as the abundance of mRNAs and proteins and (in)activation of implicated signaling networks without determining actual flux rates. In this review, we will discuss the importance of obtaining kinetic information, basic principles of stable isotope tracer methodology, calculations of in vivo glucose kinetics, and assessments of metabolic flux in experimental models in vivo and in vitro.
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Affiliation(s)
- Il-Young Kim
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon, Seoul,
Korea
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Seoul,
Korea
| | - Sanghee Park
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon, Seoul,
Korea
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Seoul,
Korea
| | - Yeongmin Kim
- Department of Health Sciences and Technology, Gachon Advanced Institute for Health Sciences & Technology (GAIHST), Gachon University, Incheon, Seoul,
Korea
| | - Yewon Chang
- Department of Health Sciences and Technology, Gachon Advanced Institute for Health Sciences & Technology (GAIHST), Gachon University, Incheon, Seoul,
Korea
| | - Cheol Soo Choi
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon, Seoul,
Korea
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Seoul,
Korea
| | - Sang-Hoon Suh
- Department of Physical Education, Yonsei University, Seoul,
Korea
| | - Robert R. Wolfe
- Department of Geriatrics, the Center for Translational Research in Aging & Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR,
USA
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A Lowly Digestible-Starch Diet after Weaning Enhances Exogenous Glucose Oxidation Rate in Female, but Not in Male, Mice. Nutrients 2019; 11:nu11092242. [PMID: 31540385 PMCID: PMC6770467 DOI: 10.3390/nu11092242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/10/2019] [Accepted: 09/16/2019] [Indexed: 11/16/2022] Open
Abstract
Starches of low digestibility are associated with improved glucose metabolism. We hypothesise that a lowly digestible-starch diet (LDD) versus a highly digestible-starch diet (HDD) improves the capacity to oxidise starch, and that this is sex-dependent. Mice were fed a LDD or a HDD for 3 weeks directly after weaning. Body weight (BW), body composition (BC), and digestible energy intake (dEI) were determined weekly. At the end of the intervention period, whole-body energy expenditure (EE), respiratory exchange ratio (RER), hydrogen production, and the oxidation of an oral 13C-labelled starch bolus were measured by extended indirect calorimetry. Pancreatic amylase activity and total 13C hepatic enrichment were determined in females immediately before and 4 h after administration of the starch bolus. For both sexes, BW, BC, and basal EE and RER were not affected by the type of starch, but dEI and hydrogen production were increased by the LDD. Only in females, total carbohydrate oxidation and starch-derived glucose oxidation in response to the starch bolus were higher in LDD versus HDD mice; this was not accompanied by differences in amylase activity or hepatic partitioning of the 13C label. These results show that starch digestibility impacts glucose metabolism differently in females versus males.
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