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Mantha OL, Mahé M, Mahéo K, Fromont G, Guéguinou M, Tea I, Hankard R, De Luca A. Understanding natural isotopic variations in cultured cancer cells. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9878. [PMID: 39117991 DOI: 10.1002/rcm.9878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 06/14/2024] [Accepted: 07/15/2024] [Indexed: 08/10/2024]
Abstract
RATIONALE Natural variations in the abundance of the stable isotopes of nitrogen (δ15N) and carbon (δ13C) offer valuable insights into metabolic fluxes. In the wake of strong interest in cancer metabolism, recent research has revealed δ15N and δ13C variations in cancerous compared to non-cancerous tissues and cell lines. However, our understanding of natural isotopic variations in cultured mammalian cells, particularly in relation to metabolism, remains limited. This study aims to start addressing this gap using metabolic modulations in cells cultured under controlled conditions. METHODS Prostate cancer cells (PC3) were cultured in different conditions and their δ15N and δ13C were measured using isotope ratio mass spectrometry. Isotopic variations during successive cell culture passages were assessed and two widely used cell culture media (RPMI and DMEM) were compared. Metabolism was modulated through glutamine deprivation and hypoxia. RESULTS Successive cell culture passages generally resulted in reproducible δ15N and δ13C values. The impact of culture medium composition on δ15N and δ13C of the cells highlights the importance of maintaining a consistent medium composition across conditions whenever possible. Glutamine deprivation and hypoxia induced a lower δ13C in bulk cell samples, with only the former affecting δ15N. Gaps between theory and experiments were bridged and the lessons learned throughout the process are provided. CONCLUSIONS Exposing cultured cancer cells to hypoxia allowed us to further investigate the relation between metabolic modulations and natural isotopic variations, while mitigating the confounding impact of changing culture medium composition. This study highlights the potential of natural δ13C variations for studying substrate fluxes and nutrient allocation in reproducible culture conditions. Considering cell yield and culture medium composition is pivotal to the success of this approach.
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Affiliation(s)
- Olivier L Mantha
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
| | - Marie Mahé
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
- Institut de Cancérologie de l'Ouest, Angers, France
| | - Karine Mahéo
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
| | - Gaëlle Fromont
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
| | - Maxime Guéguinou
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
| | - Illa Tea
- Nantes Université, CNRS, CEISAM, UMR6230, Nantes, France
| | - Régis Hankard
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
| | - Arnaud De Luca
- Niche, Nutrition, Cancer & Oxidative Metabolism (N2COX) UMR 1069, University of Tours, INSERM, Tours, France
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2
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The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients. PLoS One 2019; 14:e0219756. [PMID: 31412042 PMCID: PMC6693779 DOI: 10.1371/journal.pone.0219756] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 07/01/2019] [Indexed: 01/15/2023] Open
Abstract
Background This retrospective study had two main aims: (1) to document possible correlations between plasma Amino Acids (AAs) and circulating Albumin (Alb) and Haemoglobin (Hb); and (2) to identify which AAs were predictors of Alb and Hb. Methods The study considered 125 stroke subjects (ST) (61.6% males; 65.6 +/- 14.9 years) who met the eligibility criteria (absence of co morbidities associated with altered plasma AAs and presence of plasma AAs determined after overnight fasting). Fifteen matched healthy subjects with measured plasma AAs served as controls. Results The best correlations of Alb were with tryptophan (Trp) and histidine (His) (r = + 0.53; p < 0.0001), and those of Hb were with histidine (r = +0.47) and Essential AAs (r = +0.47) (both p<0.0001). In multivariate analysis, Trp (p< 0.0001) and His (p = 0.01) were shown to be the best positive predictors of Alb, whereas glutamine (p = 0.006) was the best positive predictor of Hb. Conclusions The study shows that the majority of plasma AAs were positively correlated with Alb and Hb. The best predictors of circulating Alb and Hb were the levels of tryptophan and glutamine, respectively.
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Roshanravan B, Zelnick LR, Djucovic D, Gu H, Alvarez JA, Ziegler TR, Gamboa JL, Utzschneider K, Kestenbaum B, Himmelfarb J, Kahn SE, Raftery D, de Boer IH. Chronic kidney disease attenuates the plasma metabolome response to insulin. JCI Insight 2018; 3:122219. [PMID: 30135309 DOI: 10.1172/jci.insight.122219] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/03/2018] [Indexed: 12/19/2022] Open
Abstract
Chronic kidney disease (CKD) leads to decreased sensitivity to the metabolic effects of insulin, contributing to protein energy wasting and muscle atrophy. Targeted metabolomics profiling during hyperinsulinemic-euglycemic insulin clamp testing may help identify aberrant metabolic pathways contributing to insulin resistance in CKD. Using targeted metabolomics profiling, we examined the plasma metabolome in 95 adults without diabetes in the fasted state (58 with CKD, 37 with normal glomerular filtration rate [GFR]) who underwent hyperinsulinemic-euglycemic clamp. We assessed heterogeneity in fasting metabolites and the response to insulin to identify potential metabolic pathways linking CKD with insulin resistance. Baseline differences and effect modification by CKD status on changes with insulin clamp testing were adjusted for confounders. Mean GFR among participants with CKD was 37.3 compared with 89.3 ml/min per 1.73 m2 among controls. Fasted-state differences between CKD and controls included abnormalities in tryptophan metabolism, ubiquinone biosynthesis, and the TCA cycle. Insulin infusion markedly decreased metabolite levels, predominantly amino acids and their metabolites. CKD was associated with attenuated insulin-induced changes in nicotinamide, arachidonic acid, and glutamine/glutamate metabolic pathways. Metabolomics profiling suggests disruption in amino acid metabolism and mitochondrial function as putative manifestations or mechanisms of the impaired anabolic effects of insulin in CKD.
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Affiliation(s)
- Baback Roshanravan
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Leila R Zelnick
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Daniel Djucovic
- Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Haiwei Gu
- Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA.,Center for Metabolic and Vascular Biology, School of Nutrition and Health Promotion, College of Health Solutions, Arizona State University, Phoenix, Arizona, USA
| | - Jessica A Alvarez
- Division of Endocrinology, Metabolism and Lipids, Emory University, Atlanta, Georgia, USA
| | - Thomas R Ziegler
- Division of Endocrinology, Metabolism and Lipids, Emory University, Atlanta, Georgia, USA
| | - Jorge L Gamboa
- Department of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Kristina Utzschneider
- Puget Sound Health Care System, Seattle, Washington, USA.,Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington, USA
| | - Bryan Kestenbaum
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Jonathan Himmelfarb
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Steven E Kahn
- Puget Sound Health Care System, Seattle, Washington, USA.,Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington, USA
| | - Daniel Raftery
- Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Ian H de Boer
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, USA.,Puget Sound Health Care System, Seattle, Washington, USA
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Roucher VF, Desnots E, Naël C, Agnoux AM, Alexandre-Gouabau MC, Darmaun D, Boquien CY. Use of UPLC-ESI-MS/MS to quantitate free amino acid concentrations in micro-samples of mammalian milk. SPRINGERPLUS 2013; 2:622. [PMID: 24298434 PMCID: PMC3841331 DOI: 10.1186/2193-1801-2-622] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/16/2013] [Indexed: 01/09/2023]
Abstract
Although free amino acids (FAA) account for a small fraction of total nitrogen in mammalian milk, they are more abundant in human milk than in most formulas, and may serve as a readily available source of amino acids for protein synthesis, as well as fulfill specific physiologic roles. We used reversed phase Ultra Performance Liquid Chromatography (UPLC) coupled to electrospray ionization tandem mass spectrometry (ESI-MS/MS) technique for FAA profiling in milks from three species (human, rat and cow) with a simple and rapid sample preparation. The derivatization procedure chosen, combined with UPLC-ESI-MS/MS allowed the quantitation of 21 FAA using labeled amino acids (Internal Standards) over a 10 min run time in micro-samples of mammalian milk (50 μL). The low limit of quantitation was 0.05 pmol/μL for most FAA with good repeatability and reproducibility (mean CV of 5.1%). Higher levels of total FAA were found in human (3032 μM) and rat milk (3460 μM) than in bovine milk (240 μM), with wide differences in the abundances of specific FAA between species. This robust analytical method could be applied to monitor FAA profile in human breast milk, and open the way to individualized adjustment of FAA content for the nutritional management of infants.
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Affiliation(s)
- Véronique Ferchaud Roucher
- IMAD, DHU 2020, CHU Hôtel-Dieu, Nantes, F-44 000 France ; INRA, UMR 1 280 Physiologie des Adaptations Nutritionnelles, Nantes, F-44 000 France ; IMAD, DHU 2020, CHU Hôtel-Dieu, Nantes, F-44 000 France
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5
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Affiliation(s)
- Milan Holecek
- Charles University in Prague, Hradec Kralove, Czech Republic
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Alexander D, Lombardi R, Rodriguez G, Mitchell MM, Marian AJ. Metabolomic distinction and insights into the pathogenesis of human primary dilated cardiomyopathy. Eur J Clin Invest 2011; 41:527-38. [PMID: 21155767 PMCID: PMC3071865 DOI: 10.1111/j.1365-2362.2010.02441.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Metabolomics, the comprehensive profile of small-molecule metabolites found in biological specimens, has the potential to provide insights into the pathogenesis of disease states and lead to the identification of new biomarkers. METHODS AND RESULTS We analysed 451 plasma metabolites by liquid chromatography/mass spectroscopy and gas chromatography/mass spectroscopy in 39 patients with primary dilated cardiomyopathy (DCM) and 31 age-, sex- and body mass index-matched controls. Sixty-one metabolites were significantly different between primary DCM and control individuals [false discovery rate (FDR) < 0·05]. Plasma levels of steroid metabolites, glutamine, threonine and histidine were reduced while levels of citric acid cycle intermediates and lipid β-oxidation products were increased in patients with primary DCM when compared to controls. Medications, particularly furosemide and angiotensin-1 converting enzyme-1 inhibitors, had significant effects on the plasma metabolites. Reduced levels of glutamine in conjunction with increased 3-methyhistidine and prolylhydroxyproline levels suggested enhanced myofibrillar and collagen degradation in DCM patients. Likewise, increased stachydrine and reduced indole-3-propionate implicated a role for intestinal-derived antioxidant molecules. Changes in steroid metabolites were notable for the loss of metabolic distinction between men and women in patients with primary DCM. Cortisol and cortisone levels were increased while androgen metabolites were decreased significantly, implying metabolic 'feminization' of men with primary DCM. CONCLUSIONS Metabolomic profiling identifies biologically active metabolites that could serve as markers of primary DCM and impart protective or harmful effects on cardiac structure and function.
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Scaglia F. New insights in nutritional management and amino acid supplementation in urea cycle disorders. Mol Genet Metab 2010; 100 Suppl 1:S72-6. [PMID: 20299258 PMCID: PMC4831209 DOI: 10.1016/j.ymgme.2010.02.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 02/23/2010] [Indexed: 01/09/2023]
Abstract
Sodium phenylbutyrate is used in the pharmacological treatment of urea cycle disorders to create alternative pathways for nitrogen excretion. The primary metabolite, phenylacetate, conjugates glutamine in the liver and kidney to form phenylacetylglutamine that is readily excreted in the urine. Patients with urea cycle disorders taking sodium phenylbutyrate have a selective reduction in the plasma concentrations of branched chain amino acids despite adequate dietary protein intake. Moreover, this depletion is usually the harbinger of a metabolic crisis. Plasma branched chain amino acids and other essential amino acids were measured in control subjects, untreated ornithine transcarbamylase deficiency females, and treated patients with urea cycle disorders (ornithine transcarbamylase deficiency and argininosuccinate synthetase deficiency) in the absorptive state during the course of stable isotope studies. Branched chain amino acid levels were significantly lower in treated patients with urea cycle disorders when compared to untreated ornithine transcarbamylase deficiency females or control subjects. These results were replicated in control subjects who had low steady-state branched chain amino acid levels when treated with sodium phenylbutyrate. These studies suggested that alternative pathway therapy with sodium phenylbutyrate causes a substantial impact on the metabolism of branched chain amino acids in patients with urea cycle disorders, implying that better titration of protein restriction can be achieved with branched chain amino acid supplementation in these patients who are on alternative pathway therapy.
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Affiliation(s)
- Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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Mok E, Letellier G, Cuisset JM, Denjean A, Gottrand F, Alberti C, Hankard R. Lack of functional benefit with glutamine versus placebo in Duchenne muscular dystrophy: a randomized crossover trial. PLoS One 2009; 4:e5448. [PMID: 19421321 PMCID: PMC2673684 DOI: 10.1371/journal.pone.0005448] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 04/08/2009] [Indexed: 11/19/2022] Open
Abstract
Background Oral glutamine decreases whole body protein breakdown in Duchenne muscular dystrophy (DMD). We evaluated the functional benefit of 4 months oral glutamine in DMD. Methodology/Principal Findings 30 ambulant DMD boys were included in this double-blind, randomized crossover trial with 2 intervention periods: glutamine (0.5 g/kg/d) and placebo, 4 months each, separated by a 1-month wash-out, at 3 outpatient clinical investigation centers in France. Functional benefit was tested by comparing glutamine versus placebo on change in walking speed at 4 months. Secondary outcome measures were: 2-minute walk test, work, power, muscle mass (urinary creatinine), markers of myofibrillar protein breakdown (urinary 3-methyl-histidine/creatinine), serum creatine phospho-kinase, body composition (fat free mass, fat mass percentage), safety and oral nutrient intake. There was no improvement in the primary end point (walking speed) or in secondary measures of muscle function (2-minute walk test, work, power) in the glutamine group compared with placebo. However, subjects receiving glutamine or placebo showed no deterioration in functional measures over the course of the 9-month trial. No differences in muscle mass, markers of protein breakdown or serum creatine phosho-kinase were observed, except for a blunted increase in fat free mass in the glutamine group which led to a greater increase in fat mass percentage. Glutamine was safe and well-tolerated. Conclusions This trial did not identify additional benefit of 4 months oral glutamine over placebo on muscle mass or function in ambulatory DMD boys. Although apparently safe, current data cannot support routine supplementation in this population as a whole, until further research proves otherwise. Trial Registration ClinicalTrials.gov NCT00296621
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Affiliation(s)
- Elise Mok
- INSERM Centre D'Investigation Clinique 802, CHU de Poitiers, Poitiers, France
- Pédiatrie Multidisciplinaire – Nutrition de l'Enfant, CHU de Poitiers, Poitiers, France
- EA3813 Laboratoire Adaptation Physiologique aux Activités Physiques, Université de Poitiers, Poitiers, France
| | - Guy Letellier
- INSERM Centre D'Investigation Clinique 802, CHU de Poitiers, Poitiers, France
- Pédiatrie Multidisciplinaire – Nutrition de l'Enfant, CHU de Poitiers, Poitiers, France
| | - Jean-Marie Cuisset
- INSERM Centre D'Investigation Clinique 9301, CHR&U de Lille, Lille, France
- Service de Neuropédiatrie et Centre de Référence National des Maladies Neuromusculaires, CHR&U de Lille, Hôpital Roger-Salengro, Lille, France
| | - André Denjean
- INSERM Centre D'Investigation Clinique 9202, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Frédéric Gottrand
- INSERM Centre D'Investigation Clinique 9301, CHR&U de Lille, Lille, France
- EA 3925, IFR 114, Faculté de Médecine, Université Lille 2, Lille, France
| | - Corinne Alberti
- Unité d'Epidémiologie Clinique et INSERM, CIE5, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Régis Hankard
- INSERM Centre D'Investigation Clinique 802, CHU de Poitiers, Poitiers, France
- Pédiatrie Multidisciplinaire – Nutrition de l'Enfant, CHU de Poitiers, Poitiers, France
- EA3813 Laboratoire Adaptation Physiologique aux Activités Physiques, Université de Poitiers, Poitiers, France
- * E-mail:
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Ferrara CT, Wang P, Neto EC, Stevens RD, Bain JR, Wenner BR, Ilkayeva OR, Keller MP, Blasiole DA, Kendziorski C, Yandell BS, Newgard CB, Attie AD. Genetic networks of liver metabolism revealed by integration of metabolic and transcriptional profiling. PLoS Genet 2008; 4:e1000034. [PMID: 18369453 PMCID: PMC2265422 DOI: 10.1371/journal.pgen.1000034] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 02/11/2008] [Indexed: 11/19/2022] Open
Abstract
Although numerous quantitative trait loci (QTL) influencing disease-related phenotypes have been detected through gene mapping and positional cloning, identification of the individual gene(s) and molecular pathways leading to those phenotypes is often elusive. One way to improve understanding of genetic architecture is to classify phenotypes in greater depth by including transcriptional and metabolic profiling. In the current study, we have generated and analyzed mRNA expression and metabolic profiles in liver samples obtained in an F2 intercross between the diabetes-resistant C57BL/6 leptinob/ob and the diabetes-susceptible BTBR leptinob/ob mouse strains. This cross, which segregates for genotype and physiological traits, was previously used to identify several diabetes-related QTL. Our current investigation includes microarray analysis of over 40,000 probe sets, plus quantitative mass spectrometry-based measurements of sixty-seven intermediary metabolites in three different classes (amino acids, organic acids, and acyl-carnitines). We show that liver metabolites map to distinct genetic regions, thereby indicating that tissue metabolites are heritable. We also demonstrate that genomic analysis can be integrated with liver mRNA expression and metabolite profiling data to construct causal networks for control of specific metabolic processes in liver. As a proof of principle of the practical significance of this integrative approach, we illustrate the construction of a specific causal network that links gene expression and metabolic changes in the context of glutamate metabolism, and demonstrate its validity by showing that genes in the network respond to changes in glutamine and glutamate availability. Thus, the methods described here have the potential to reveal regulatory networks that contribute to chronic, complex, and highly prevalent diseases and conditions such as obesity and diabetes. Although numerous quantitative trait loci (QTL) influencing disease-related phenotypes have been detected through gene mapping and positional cloning, identifying individual genes and their potential roles in molecular pathways leading to disease remains a challenge. In this study, we include transcriptional and metabolic profiling in genomic analyses to address this limitation. We investigated an F2 intercross between the diabetes-resistant C57BL/6 leptinob/ob and the diabetes-susceptible BTBR leptinob/ob mouse strains that segregates for genotype and diabetes-related physiological traits; blood glucose, plasma insulin and body weight. Our study shows that liver metabolites (comprised of amino acids, organic acids, and acyl-carnitines) map to distinct genetic regions, thereby indicating that tissue metabolites are heritable. We also demonstrate that genomic analysis can be integrated with liver mRNA expression and metabolite profiling data to construct causal, testable networks for control of specific metabolic processes in liver. We apply an in vitro study to confirm the validity of this integrative method, and thus provide a novel approach to reveal regulatory networks that contribute to chronic, complex, and highly prevalent diseases and conditions such as obesity and diabetes.
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Affiliation(s)
- Christine T. Ferrara
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail: (CTF); (CBN); (ADA)
| | - Ping Wang
- Department of Statistics, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Elias Chaibub Neto
- Department of Statistics, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Robert D. Stevens
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - James R. Bain
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Brett R. Wenner
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Olga R. Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Mark P. Keller
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Daniel A. Blasiole
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Brian S. Yandell
- Department of Statistics, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Christopher B. Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail: (CTF); (CBN); (ADA)
| | - Alan D. Attie
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail: (CTF); (CBN); (ADA)
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Mignon M, Lêvêque L, Bonnel E, Meynial-Denis D. Does glutamine supplementation decrease the response of muscle glutamine synthesis to fasting in muscle in adult and very old rats? JPEN J Parenter Enteral Nutr 2007; 31:26-31. [PMID: 17202437 DOI: 10.1177/014860710703100126] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Glutamine synthetase (GS), a key enzyme in the production of glutamine, is preserved in rat skeletal muscle during aging but is increased with advanced age in vivo. The aim of this study was to determine whether glutamine supplementation affects up-regulation of GS by fasting in vivo in adult and very old female rats. METHODS Muscle GS activities were assessed in 5-day-fasted female Wistar adult (6 months) and very old (27 months) rats refed and supplemented with glutamine or other amino acids (alanine or glycine). Fed rats were used to investigate the possible effect of glutamine supplementation in the fed state. RESULTS After 5 days' fasting, the up-regulated GS activity was decreased whatever the type of amino acid supplementation (glutamine, alanine, and glycine) in adults, whereas it was only decreased by glutamine supplementation in very old rats). In the fed state, no effect of glutamine supplementation was observed even if GS activity remained up-regulated whatever the age and the period of supplementation. CONCLUSIONS These results confirm that glutamine has a specific role in very old rats. The up-regulated GS activity was decreased by an exogenous supply of glutamine only if intramuscular glutamine was depleted; this was confirmed by studies in the fed state. The up-regulated GS activity in both fed and fasted rats may be associated with increased glutamine requirements in the whole body.
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Le Bacquer O, Mauras N, Welch S, Haymond M, Darmaun D. Acute depletion of plasma glutamine increases leucine oxidation in prednisone-treated humans. Clin Nutr 2006; 26:231-8. [PMID: 17097772 PMCID: PMC1949027 DOI: 10.1016/j.clnu.2006.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 08/26/2006] [Accepted: 09/27/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND, AIMS & METHODS To determine whether depletion in plasma glutamine worsens the catabolic response to corticosteroids, seven healthy volunteers received oral prednisone for 6 days on two separate occasions, at least 2 weeks apart, and in random order. On the sixth day of each treatment course, they received 5 h intravenous infusions of L-[1-(14)C]-leucine and L-[1-(13)C]-glutamine in the postabsorptive state (1) under baseline conditions (prednisone only day) and (2) after 24h of treatment with phenylbutyrate (prednisone+phenylbutyrate day), a glutamine chelating agent. RESULTS Phenylbutyrate treatment was associated with (1) an approximately 15% decline in plasma glutamine concentration (627+/-39 vs. 530+/-31 micromol l(-1); P<0.05), (2) no change in leucine appearance rate, an index of protein breakdown (124+/-9 vs. 128+/-9 micromol kg(-1) h(-1); NS) nor in non-oxidative leucine disposal, an index of whole body protein synthesis (94+/-9 vs. 91+/-7 micromol kg(-1) h(-1); NS), and (3) a approximately 25% rise in leucine oxidation (30+/-1 vs. 38+/-2 micromol kg(-1) h(-1), P<0.05), despite an approximately 25% decline (P<0.05) in leucine concentration. CONCLUSIONS In a model of mild, stress-induced protein catabolism, depletion of plasma glutamine per se may worsen branched chain amino acid and protein wasting.
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Affiliation(s)
| | - Nelly Mauras
- Division of Endocrinology, Nemours Children’s Clinic, Jacksonville, Florida
| | - Susan Welch
- Division of Endocrinology, Nemours Children’s Clinic, Jacksonville, Florida
| | - Morey Haymond
- USDA Children’s Nutrition Research Center at Baylor College of Medicine, Houston, Texas
| | - Dominique Darmaun
- Division of Endocrinology, Nemours Children’s Clinic, Jacksonville, Florida
- INSERM U.539, Centre de Recherche en Nutrition Humaine, Nantes, France
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Abstract
Appropriate nutrition is an essential prerequisite for effective improvement of athletic performance, conditioning, recovery from fatigue after exercise, and avoidance of injury. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. In addition, several natural food components have been found to show physiological effects, and some of them are considered to be useful for promoting exercise performance or for prevention of injury. However, these foods should only be used when there is clear scientific evidence and with understanding of the physiological changes caused by exercise. This article describes various "functional foods" that have been reported to be effective for improving exercise performance or health promotion, along with the relevant physiological changes that occur during exercise.
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Affiliation(s)
- Wataru Aoi
- Research Center for Sports Medicine, Doshisha University, Kyoto 602-8580, Japan
- Department of Inflammation and Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Yuji Naito
- Department of Medical Proteomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Toshikazu Yoshikawa
- Department of Inflammation and Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
- Department of Medical Proteomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Meynial-Denis D, Verdier L, Mignon M, Leclerc JN, Bayle G, Darmaun D. Does acute glutamine depletion enhance the response of glutamine synthesis to fasting in muscle in adult and old rats? Clin Nutr 2005; 24:398-406. [PMID: 15896426 DOI: 10.1016/j.clnu.2004.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2004] [Accepted: 12/17/2004] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS In earlier studies, skeletal muscle glutamine synthetase (GS) activity was shown to be enhanced by fasting and glucocorticoids, and inhibited by exogenous glutamine (Gln) supplementation. The current study was designed to determine whether phenylbutyrate (PhiB), a Gln-chelating agent in humans, (1) could trap Gln and produce a decline in plasma Gln in rats, as it does in humans, and (2) if so, whether (Phi)B would further enhance the response of muscle GS activity to fasting in rats. METHODS Adult (6-8 months) and aged (20-21 months) rats were fasted for 5 days and received two doses of 0.5 g(Phi)Bby orogastric route at times 0 and 4 h, and were then sacrificed at 5.5 h. Plasma Gln was measured by enzymatic methods, other amino acids were quantified by amino acid analysis. GS activity was measured in soleus (SO) and tibialis anterior (TA) muscles. RESULTS (Phi)B treatment was associated with: (1) a 20% decline in plasma Gln concentration from 572+/-54 to 424+/-34 micromol/L (P<0.05) and from 476+/-49 to 360+/-80 micromol/L (P<0.05) in fasted adult and old rats, respectively; and (2) a preservation of GS up-regulation by fasting in TA and SO muscles in both adult and aged rats, with TA muscle GS activities of 198+/-65 vs. 203+/-68 ((Phi)B-treated vs. vehicle-treated, NS), and 244+/-81 vs. 274+/-59 (NS) nmol/h/mg protein in adult and aged rats, respectively. CONCLUSION These data suggest that: (1) large doses of (Phi)B deplete plasma Gln in fasted rats, regardless of age, (2) Gln depletion induced by Phi)B does not alter GS activity.
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Affiliation(s)
- Dominique Meynial-Denis
- Human Nutrition Research Center at Clermont-Ferrand, and Institut National de la Recherche Agronomique, Nutrition and Protein Metabolism Unit, Theix, 63122 Saint Genès Champanelle, France.
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Coëffier M, Claeyssens S, Hecketsweiler B, Lavoinne A, Ducrotté P, Déchelotte P. Enteral glutamine stimulates protein synthesis and decreases ubiquitin mRNA level in human gut mucosa. Am J Physiol Gastrointest Liver Physiol 2003; 285:G266-73. [PMID: 12702496 DOI: 10.1152/ajpgi.00385.2002] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Effects of glutamine on whole body and intestinal protein synthesis and on intestinal proteolysis were assessed in humans. Two groups of healthy volunteers received in a random order enteral glutamine (0.8 mmol.kg body wt(-1)x h(-1)) compared either to saline or isonitrogenous amino acids. Intravenous [2H5]phenylalanine and [13C]leucine were simultaneously infused. After gas chromatography-mass spectrometry analysis, whole body protein turnover was estimated from traced plasma amino acid fluxes and the fractional synthesis rate (FSR) of gut mucosal protein was calculated from protein and intracellular phenylalanine and leucine enrichments in duodenal biopsies. mRNA levels for ubiquitin, cathepsin D, and m-calpain were analyzed in biopsies by RT-PCR. Glutamine significantly increased mucosal protein FSR compared with saline. Glutamine and amino acids had similar effects on FSR. The mRNA level for ubiquitin was significantly decreased after glutamine infusion compared with saline and amino acids, whereas cathepsin D and m-calpain mRNA levels were not affected. Enteral glutamine stimulates mucosal protein synthesis and may attenuate ubiquitin-dependent proteolysis and thus improve protein balance in human gut.
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Affiliation(s)
- Moïse Coëffier
- Appareil Digestif, Environnement et Nutrition, Institut Fédératif de Recherche Multidisciplinaire sur les Peptides, Centre d' Investigation Clinique, Rouen, France
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15
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Le Bacquer O, Laboisse C, Darmaun D. Glutamine preserves protein synthesis and paracellular permeability in Caco-2 cells submitted to "luminal fasting". Am J Physiol Gastrointest Liver Physiol 2003; 285:G128-36. [PMID: 12799310 DOI: 10.1152/ajpgi.00459.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study used polarized cell line Caco-2 as a model of human enterocytes to determine: 1) whether deprivation of nutrients on the apical (luminal) side of the epithelium (fasting) alters protein synthesis in enterocytes; 2) if so, whether glutamine can attenuate the effects of fasting; and 3) whether the effects of glutamine depend on its route (i.e., apical vs. basolateral) of supply. Caco-2 cells were submitted to nutrient deprivation on the apical side to mimic the effects of fasting, whereas the basolateral side of the epithelium remained exposed to regular medium. Cells were then incubated with [2H3]leucine with or without glutamine, and the fractional synthesis rate (FSR) of total cell protein was determined from [2H3]leucine enrichments in protein-bound and intracellular free leucine measured by gas chromatography/mass spectrometry. A 24-h apical nutrient deprivation (luminal fasting) was associated with a decline in intracellular glutamine, glutamate, and glutathione concentrations (-38, -40, and -40%, respectively), protein FSR (-20%), and a rise in passage of dextran, an index of transepithelial permeability. In fasted cells, basolateral or luminal glutamine supplementation did not alter the glutathione pool, but it restored protein FSR and improved permeability. The effects of glutamine were abolished by 6-diazo-oxo-l-norleucine, an inhibitor of glutaminase, and was mimicked by glutamate. We conclude that in Caco-2 cells, protein synthesis depends on nutrient supply on the apical side, and glutamine regardless of the route of supply corrects some of the deleterious effects of fasting in a model of human enterocytes through its deamidation into glutamate.
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Affiliation(s)
- Olivier Le Bacquer
- INSERM U.539, Centre de Recherche en Nutrition Humaine Groupe Métabolisme, Hotel-Dieu, 3ème étage aile nord, 44093 Nantes cedex 1, France
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16
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Humbert B, Martin L, Dumon H, Darmaun D, Nguyen P. Dietary protein level affects protein metabolism during the postabsorptive state in dogs. J Nutr 2002; 132:1676S-8S. [PMID: 12042490 DOI: 10.1093/jn/132.6.1676s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Bernard Humbert
- Laboratory of Nutrition and Endocrinology, National Veterinary School of Nantes and INSERM U.539, Human Nutrition Research Center, Nantes, France
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17
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Caso G, Ford GC, Nair KS, Garlick PJ, McNurlan MA. Aminoacyl-tRNA enrichment after a flood of labeled phenylalanine: insulin effect on muscle protein synthesis. Am J Physiol Endocrinol Metab 2002; 282:E1029-38. [PMID: 11934667 DOI: 10.1152/ajpendo.00215.2001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Muscle protein synthesis in dogs measured by flooding with L-[(2)H(5)]phenylalanine (70 mg/kg) was significantly stimulated by infusion of insulin with amino acids. The stimulation of muscle protein synthesis was similar when calculated from the enrichment of phenylalanyl-tRNA (61 +/- 10%, P < 0.001), plasma phenylalanine (61 +/- 10%, P < 0.001), or tissue fluid phenylalanine (54 +/- 10%, P < 0.001). The time course for changes in enrichment of L-[(2)H(5)]phenylalanine throughout the flooding period was determined for plasma, tissue fluid, and phenylalanyl-tRNA in the basal state and during the infusion of insulin with amino acids. Enrichments of plasma free phenylalanine and phenylalanyl-tRNA were equalized between 20 and 45 min, although the enrichment of phenylalanyl-tRNA was lower at early time points. Rates of muscle protein synthesis obtained with the flooding method and calculated from plasma phenylalanine enrichment were comparable to those calculated from phenylalanyl-tRNA and also to those obtained previously with a continuous infusion of phenylalanine with phenylalanyl-tRNA as precursor. This study confirms that, with a bolus injection of labeled phenylalanine, the enrichment of aminoacyl-tRNA, the true precursor pool for protein synthesis, can be assessed from more readily sampled plasma phenylalanine.
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Affiliation(s)
- Giuseppe Caso
- Department of Surgery, State University of New York, Stony Brook, New York 11794-8191, USA.
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Le Bacquer O, Nazih H, Blottière H, Meynial-Denis D, Laboisse C, Darmaun D. Effects of glutamine deprivation on protein synthesis in a model of human enterocytes in culture. Am J Physiol Gastrointest Liver Physiol 2001; 281:G1340-7. [PMID: 11705738 DOI: 10.1152/ajpgi.2001.281.6.g1340] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To assess the effect of glutamine availability on rates of protein synthesis in human enterocytes, Caco-2 cells were grown until differentiation and then submitted to glutamine deprivation produced by exposure to glutamine-free medium or methionine sulfoximine [L-S-[3-amino-3-carboxypropyl]-S-methylsulfoximine (MSO)], a glutamine synthetase inhibitor. Cells were then incubated with (2)H(3)-labeled leucine with or without glutamine, and the fractional synthesis rate (FSR) of total cell protein was determined from (2)H(3)-labeled enrichments in protein-bound and intracellular free leucine measured by gas chromatography-mass spectrometry. Both protein FSR (28 +/- 1.5%/day) and intracellular glutamine concentration (6.1 +/- 0.6 micromol/g protein) remained unaltered when cells were grown in glutamine-free medium. In contrast, MSO treatment resulted in a dramatic reduction in protein synthesis (4.6 +/- 0.6 vs. 20.2 +/- 0.8%/day, P < 0.01). Supplementation with 0.5-2 mM glutamine for 4 h after MSO incubation, but not with glycine nor glutamate, restored protein FSR to control values (24 +/- 1%/day). These results demonstrate that in Caco-2 cells, 1) de novo glutamine synthesis is highly active, since it can maintain intracellular glutamine pool during glutamine deprivation, 2) inhibition of glutamine synthesis is associated with reduced protein synthesis, and 3) when glutamine synthesis is depressed, exogenous glutamine restores normal intestinal FSR. Due to the limitations intrinsic to the use of a cell line as an experimental model, the physiological relevance of these findings for the human intestine in vivo remains to be determined.
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Affiliation(s)
- O Le Bacquer
- INSERM U.539, Centre de Recherche en Nutrition Humaine, 44093 Nantes, France
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Devaux Y, Grosjean S, Seguin C, David C, Dousset B, Zannad F, Meistelman C, De Talancé N, Mertes PM, Ungureanu-Longrois D. Retinoic acid and host-pathogen interactions: effects on inducible nitric oxide synthase in vivo. Am J Physiol Endocrinol Metab 2000; 279:E1045-53. [PMID: 11052959 DOI: 10.1152/ajpendo.2000.279.5.e1045] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vitamin A and its metabolite retinoic acid modulate the host response to pathogens through poorly characterized mechanisms. In vitro studies have suggested that retinoic acid decreases inducible NO synthase (NOS2, or iNOS) expression, a component of innate immunity, in several cell types stimulated with lipopolysaccharide (LPS) or cytokines. This study investigated the effect of retinoic acid on LPS-stimulated NOS2 expression in vivo. Wistar-Kyoto rats received all-trans retinoic acid (RA, 10 mg/kg) or vehicle intraperitoneally daily for 5 days followed by LPS (4 mg/kg) or saline intraperitoneally and were killed 6 h later. NOS2 activation was estimated by mRNA (RT-PCR) and protein (Western-blot) expression and plasma nitrate/nitrite accumulation. In sharp contrast to previous in vitro study reports, RA significantly enhanced NOS2 mRNA, protein expression, and plasma nitrate/nitrite concentration in LPS-injected rats but not in saline-injected rats. This was associated with increased expression of interleukin-2, interferon (IFN)-gamma and IFN regulatory factor-1 mRNAs in several organs and increased IFN-gamma plasma concentration. RA significantly increased mortality in LPS-injected rats. The NOS inhibitor aminoguanidine (50 mg/kg before LPS injection) significantly attenuated the RA-mediated increase in mortality. These results demonstrate for the first time that RA supplementation in vivo enhances activation of the LPS-triggered NOS2 pathway.
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Affiliation(s)
- Y Devaux
- Laboratory of Experimental Medicine and Surgery, Faculté de Médecine, 54505 Vandoeuvre, France
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Claeyssens S, Bouteloup-Demange C, Gachon P, Hecketsweiler B, Lerebours E, Lavoinne A, Déchelotte P. Effect of enteral glutamine on leucine, phenylalanine and glutamine metabolism in hypercortisolemic subjects. Am J Physiol Endocrinol Metab 2000; 278:E817-24. [PMID: 10780937 DOI: 10.1152/ajpendo.2000.278.5.e817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of enteral Gln on protein and Gln metabolism was investigated during experimental hypercortisolemia. Four groups of subjects that had received corticosteroids and either enteral Gln (0.5 g x kg(-1) x day(-1) for 2 days) or isonitrogenous Ala-Gly were studied in a fasted or in a fed state. In either state, enteral Gln, compared with Ala-Gly, induced no statistically significant change in the endogenous rate of Leu appearance, an index of proteolysis, Leu oxidation, and nonoxidative Leu disposal, an index of protein synthesis, as studied by kinetics of [1-(13)C]Leu. Similar data were obtained from kinetics of [(2)H(5)]Phe, resulting in an unchanged protein balance in both cases. In contrast, enteral Gln significantly decreased the endogenous rate of Gln appearance and Gln de novo synthesis in the fed state (P < 0.05) as estimated by the kinetics of [(15)N]Gln. This decrease in Gln de novo synthesis induced by Gln could contribute to spare amino acids in hypercatabolic patients.
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Affiliation(s)
- S Claeyssens
- Groupe de Biochimie et Physiopathologie Digestive et Nutritionnelle and Institut Fédératif de Recherches Multidisciplinaires sur les Peptides No. 23, Faculté de Médecine-Pharmacie, 76183 Rouen Cedex, France.
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Jackson NC, Carroll PV, Russell-Jones DL, Sönksen PH, Treacher DF, Umpleby AM. Effects of glutamine supplementation, GH, and IGF-I on glutamine metabolism in critically ill patients. Am J Physiol Endocrinol Metab 2000; 278:E226-33. [PMID: 10662706 DOI: 10.1152/ajpendo.2000.278.2.e226] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During critical illness glutamine deficiency may develop. Glutamine supplementation can restore plasma concentration to normal, but the effect on glutamine metabolism is unknown. The use of growth hormone (GH) and insulin-like growth factor I (IGF-I) to prevent protein catabolism in these patients may exacerbate the glutamine deficiency. We have investigated, in critically ill patients, the effects of 72 h of treatment with standard parenteral nutrition (TPN; n = 6), TPN supplemented with glutamine (TPNGLN; 0.4 g x kg(-1) x day(-1), n = 6), or TPNGLN with combined GH (0.2 IU. kg(-1). day(-1)) and IGF-I (160 microg x kg (-1) x day(-1)) (TPNGLN+GH/IGF-I; n = 5) on glutamine metabolism using [2-(15)N]glutamine. In patients receiving TPNGLN and TPNGLN+GH/IGF-I, plasma glutamine concentration was increased (338 +/- 22 vs. 461 +/- 24 micromol/l, P < 0.001, and 307 +/- 65 vs. 524 +/- 71 micromol/l, P < 0.05, respectively) and glutamine uptake was increased (5.2 +/- 0.5 vs. 7.4 +/- 0.7 micromol x kg(-1) x min(-1), P < 0.05 and 5.2 +/- 1.1 vs. 7.6 +/- 0.8 micromol x kg(-1) x min(-1), P < 0.05). Glutamine production and metabolic clearance rates were not altered by the three treatments. These results suggest that there is an increased requirement for glutamine in critically ill patients. Combined GH/IGF-I treatment with TPNGLN did not have adverse effects on glutamine metabolism.
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Affiliation(s)
- N C Jackson
- Departments of Diabetes, Endocrinology and Metabolic Medicine, St. Thomas' Hospital, London SE1 7EH, United Kingdom
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Abstract
Experimental studies have clearly demonstrated both the indispensability in stress situations of amino acids, previously considered to be non-essential, and the importance of the specific properties of these same amino acids. Glutamine, arginine and their precursors/metabolites, ornithine and alpha-ketoglutarate, exert anabolic or anticatabolic effects through their involvement in protein metabolism, in the immune response and in cell proliferation. Clinical studies suggest that the supplementation of nutritional therapy with these amino acids can be of significant benefit for injured patients.
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Affiliation(s)
- J P De Bandt
- Laboratoire de Biochimie A, Hôpital Necker-Enfants Malades, Faculté de Pharmacie, Université Paris V, France
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