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Wierzchowska-McNew RA, Engelen MPKJ, Thaden JJ, Ten Have GAM, Deutz NEP. Obesity- and sex-related metabolism of arginine and nitric oxide in adults. Am J Clin Nutr 2022; 116:1610-1620. [PMID: 36166849 DOI: 10.1093/ajcn/nqac277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/29/2022] [Accepted: 09/23/2022] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND There is growing interest in the supplementation of arginine (Arg) and citrulline (Cit) in obesity due to their potential anti-obesogenic and anti-inflammatory properties. However, there is no consensus on the metabolic changes in Arg kinetics in obesity. OBJECTIVES This exploratory cross-sectional study aimed to investigate the association between obesity, sex, and sex-by-obesity interaction on whole-body Arg kinetics in a large group of human subjects. METHODS We studied 83 nonobese [BMI (kg/m2) <30] and 80 morbidly obese (BMI >30) middle-aged individuals (40% males) enrolled in the MEDIT (Metabolism of Disease with Isotope Tracers) trial. After body-composition measurement by DXA, we collected arterial(ized) blood samples for amino acid (AA) concentrations, markers of inflammation [high-sensitivity C-reactive protein (hs-CRP)], liver function, and glucose in a postabsorptive state. We administered a pulse of AA stable tracers and measured whole-body production (WBP) of Arg, Cit, ornithine (Orn), phenylalanine, and tyrosine, and calculated their clearance (disposal capacity) and metabolite interconversions [markers for NO and de novo Arg production, systemic Arg hydrolysis, and whole-body protein breakdown (wbPB)]. We measured plasma enrichments by LC-MS/MS and statistics by Fisher's exact test or analysis of (co)variance. Significance was set at P < 0.05. RESULTS Obese individuals were normoglycemic and characterized by low-grade inflammation (P < 0.0001) and greater wbPB (P = 0.0298). We found lower plasma Cit concentration (P < 0.0001) in the obese group but no differences in the WBP of Arg, Cit, and Orn. Furthermore, we observed overproduction of NO (P < 0.0001) in obesity but lower de novo Arg production (P = 0.0007). The WBP of Arg was lower in females for almost all Arg-related AAs, except for plasma Cit and NO production. CONCLUSIONS Alterations in Arg metabolism are present in morbid obesity. Further studies are needed to investigate if these changes could be related to factors such as increased Arg requirement in obesity or metabolic adaptation.
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Affiliation(s)
- Raven A Wierzchowska-McNew
- Department of Kinesiology and Sport Management, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, TX, USA
| | - Mariëlle P K J Engelen
- Department of Kinesiology and Sport Management, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, TX, USA
| | - John J Thaden
- Department of Kinesiology and Sport Management, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, TX, USA
| | - Gabriella A M Ten Have
- Department of Kinesiology and Sport Management, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, TX, USA
| | - Nicolaas E P Deutz
- Department of Kinesiology and Sport Management, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, TX, USA
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Seasely AR, Sinkey RG, Dean SJ, Descartes M, Duncan VE. Placental Pathology in Maternal Ornithine Transcarbamylase Deficiency. Pediatr Dev Pathol 2022; 25:278-284. [PMID: 34958254 DOI: 10.1177/10935266211055286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Ornithine transcarbamylase (OTC) deficiency is the most common urea cycle disorder, inherited in an X-linked manner. Males are severely affected. Female phenotypes vary from asymptomatic to severe, and symptoms may be triggered by high metabolic states like childbirth. Literature on OTC deficiency in pregnancy and placental pathology is limited. METHODS Pathology records were searched at a single referral center from 2000-2020 and identified three placental cases from two mothers heterozygous for OTC deficiency. Placental pathology and maternal and neonatal history were reviewed in detail. RESULTS The placenta from one symptomatic mother carrying an affected male fetus showed widespread high-grade fetal vascular malperfusion (FVM) lesions of varying age. These lesions were not seen in the two placentas from the asymptomatic mother. DISCUSSION In cases of symptomatic maternal OTC deficiency, our findings highlight the need for placental examination. Since thrombotic events in the placenta have the potential to associate with fetal and neonatal endothelial damage, a high index of suspicion for neonatal thrombosis may be warranted.
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Affiliation(s)
- Angela R Seasely
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Center for Women's Reproductive Health, 9968University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Genetics, 9968University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rachel G Sinkey
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Center for Women's Reproductive Health, 9968University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sarah Joy Dean
- Department of Genetics, 9968University of Alabama at Birmingham, Birmingham, AL, USA
| | - Maria Descartes
- Department of Genetics, 9968University of Alabama at Birmingham, Birmingham, AL, USA
| | - Virginia E Duncan
- Department of Pathology, Perinatal Section, 9968University of Alabama at Birmingham, Birmingham, AL, USA
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Bernstein HG, Dobrowolny H, Keilhoff G, Steiner J. In human brain ornithine transcarbamylase (OTC) immunoreactivity is strongly expressed in a small number of nitrergic neurons. Metab Brain Dis 2017; 32:2143-2147. [PMID: 28868581 DOI: 10.1007/s11011-017-0105-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 08/29/2017] [Indexed: 12/15/2022]
Abstract
There is recent evidence for ornithine transcarbamylase (OTC) expression in adult human brain. We decided to immunocytochemically map OTC throughout brain, and to further characterize OTC-immunopositive neurons. By using double immunolabeling technique for OTC and neuronal nitric oxide synthase (nNOS) OTC protein expression was revealed in a small subset of nitrergic (nNOS) neurons. Since citrulline (the reaction product of OTC) enhances the bioavailability of L-arginine, the substrate of nNOS, it is conceivable that OTC activity supports NO production in nitrergic neurons.
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Affiliation(s)
- Hans-Gert Bernstein
- Department of Psychiatry and Psychotherapy, University of Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany.
| | - Hendrik Dobrowolny
- Department of Psychiatry and Psychotherapy, University of Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, D-39120, Magdeburg, Germany
| | - Johann Steiner
- Department of Psychiatry and Psychotherapy, University of Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
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Bourdon A, Parnet P, Nowak C, Tran NT, Winer N, Darmaun D. L-Citrulline Supplementation Enhances Fetal Growth and Protein Synthesis in Rats with Intrauterine Growth Restriction. J Nutr 2016; 146:532-41. [PMID: 26865647 DOI: 10.3945/jn.115.221267] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/04/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Intrauterine growth restriction (IUGR) results from either maternal undernutrition or impaired placental blood flow, exposing offspring to increased perinatal mortality and a higher risk of metabolic syndrome and cardiovascular disease during adulthood. l-Citrulline is a precursor of l-arginine and nitric oxide (NO), which regulates placental blood flow. Moreover, l-citrulline stimulates protein synthesis in other models of undernutrition. OBJECTIVE The aim of the study was to determine whether l-citrulline supplementation would enhance fetal growth in a model of IUGR induced by maternal dietary protein restriction. METHODS Pregnant rats were fed either a control (20% protein) or a low-protein (LP; 4% protein) diet. LP dams were randomly allocated to drink tap water either as such or supplemented with l-citrulline (2 g · kg(-1) · d(-1)), an isonitrogenous amount of l-arginine, or nonessential l-amino acids (NEAAs). On day 21 of gestation, dams received a 2-h infusion of l-[1-(13)C]-valine until fetuses were extracted by cesarean delivery. Isotope enrichments were measured in free amino acids and fetal muscle, liver, and placenta protein by GC-mass spectrometry. RESULTS Fetal weight was ∼29% lower in the LP group (3.82 ± 0.06 g) than in the control group (5.41 ± 0.10 g) (P < 0.001). Regardless of supplementation, fetal weight remained below that of control fetuses. Yet, compared with the LP group, l-citrulline and l-arginine equally increased fetal weight to 4.15 ± 0.08 g (P < 0.05) and 4.13 ± 0.1 g (P < 0.05 compared with LP), respectively, whereas NEAA did not (4.05 ± 0.05 g; P = 0.07). Fetal muscle protein fractional synthesis rate was 35% lower in the LP fetuses (41% ± 11%/d) than in the control (61% ± 13%/d) fetuses (P < 0.001) and was normalized by l-citrulline (56% ± 4%/d; P < 0.05 compared with LP, NS compared with control) and not by other supplements. Urinary nitrite and nitrate excretion was lower in the LP group (6.4 ± 0.8 μmol/d) than in the control group (17.9 ± 1.1 μmol/d; P < 0.001) and increased in response to l-citrulline or l-arginine (12.1 ± 2.2 and 10.6 ± 0.9 μmol/d; P < 0.05), whereas they did not in the LP + NEAA group. CONCLUSION l-Citrulline increases fetal growth in a model of IUGR, and the effect may be mediated by enhanced fetal muscle protein synthesis and/or increased NO production.
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Affiliation(s)
- Aurélie Bourdon
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France
| | - Patricia Parnet
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France
| | - Christel Nowak
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France; Department of Gynecology and Obstetrics, University Medical Center of Nantes, Nantes, France; and
| | - Nhat-Thang Tran
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France
| | - Norbert Winer
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France; Department of Gynecology and Obstetrics, University Medical Center of Nantes, Nantes, France; and
| | - Dominique Darmaun
- National Institute of Agricultural Research (INRA), Joint Research Unit (UMR 1280), Physiology of Nutritional Adaptations, University of Nantes, Institute for Diseases of the Digestive System (IMAD), and Western Human Nutrition Research Center (CRNH), Nantes, France; Nutrition Support Team, IMAD, University Medical Center of Nantes, Nantes, France
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Ruzsics I, Nagy L, Keki S, Sarosi V, Illes B, Illes Z, Horvath I, Bogar L, Molnar T. L-Arginine Pathway in COPD Patients with Acute Exacerbation: A New Potential Biomarker. COPD 2015; 13:139-45. [DOI: 10.3109/15412555.2015.1045973] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Wijnands KAP, Meesters DM, van Barneveld KWY, Visschers RGJ, Briedé JJ, Vandendriessche B, van Eijk HMH, Bessems BAFM, van den Hoven N, von Wintersdorff CJH, Brouckaert P, Bouvy ND, Lamers WH, Cauwels A, Poeze M. Citrulline Supplementation Improves Organ Perfusion and Arginine Availability under Conditions with Enhanced Arginase Activity. Nutrients 2015; 7:5217-38. [PMID: 26132994 PMCID: PMC4516994 DOI: 10.3390/nu7075217] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 05/15/2015] [Accepted: 06/18/2015] [Indexed: 01/10/2023] Open
Abstract
Enhanced arginase-induced arginine consumption is believed to play a key role in the pathogenesis of sickle cell disease-induced end organ failure. Enhancement of arginine availability with l-arginine supplementation exhibited less consistent results; however, l-citrulline, the precursor of l-arginine, may be a promising alternative. In this study, we determined the effects of l-citrulline compared to l-arginine supplementation on arginine-nitric oxide (NO) metabolism, arginine availability and microcirculation in a murine model with acutely-enhanced arginase activity. The effects were measured in six groups of mice (n = 8 each) injected intraperitoneally with sterile saline or arginase (1000 IE/mouse) with or without being separately injected with l-citrulline or l-arginine 1 h prior to assessment of the microcirculation with side stream dark-field (SDF)-imaging or in vivo NO-production with electron spin resonance (ESR) spectroscopy. Arginase injection caused a decrease in plasma and tissue arginine concentrations. l-arginine and l-citrulline supplementation both enhanced plasma and tissue arginine concentrations in arginase-injected mice. However, only the citrulline supplementation increased NO production and improved microcirculatory flow in arginase-injected mice. In conclusion, the present study provides for the first time in vivo experimental evidence that l-citrulline, and not l-arginine supplementation, improves the end organ microcirculation during conditions with acute arginase-induced arginine deficiency by increasing the NO concentration in tissues.
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Affiliation(s)
- Karolina A P Wijnands
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Dennis M Meesters
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Kevin W Y van Barneveld
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Ruben G J Visschers
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Jacob J Briedé
- Department of Toxicogenomics, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6200, The Netherlands.
| | - Benjamin Vandendriessche
- Department of Molecular Biomedical Research, VIB, Ghent B-9000, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent B-9000, Belgium.
| | - Hans M H van Eijk
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Babs A F M Bessems
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Nadine van den Hoven
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Christian J H von Wintersdorff
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Peter Brouckaert
- Department of Molecular Biomedical Research, VIB, Ghent B-9000, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent B-9000, Belgium.
| | - Nicole D Bouvy
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
| | - Wouter H Lamers
- Department of Anatomy & Embryology, Maastricht University Medical Center, Maastricht 6200, The Netherlands.
| | - Anje Cauwels
- Department of Molecular Biomedical Research, VIB, Ghent B-9000, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent B-9000, Belgium.
| | - Martijn Poeze
- Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands.
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Wax B, Kavazis AN, Luckett W. Effects of Supplemental Citrulline-Malate Ingestion on Blood Lactate, Cardiovascular Dynamics, and Resistance Exercise Performance in Trained Males. J Diet Suppl 2015; 13:269-82. [DOI: 10.3109/19390211.2015.1008615] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Fike CD, Summar M, Aschner JL. L-citrulline provides a novel strategy for treating chronic pulmonary hypertension in newborn infants. Acta Paediatr 2014; 103:1019-26. [PMID: 24862864 DOI: 10.1111/apa.12707] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 03/23/2014] [Accepted: 05/23/2014] [Indexed: 02/05/2023]
Abstract
UNLABELLED Effective therapies are urgently needed for infants with forms of pulmonary hypertension that develop or persist beyond the first week of life. The L-arginine nitric oxide (NO) precursor, L-citrulline, improves NO signalling and ameliorates pulmonary hypertension in newborn animals. In vitro studies demonstrate that manipulating L-citrulline transport alters NO production. CONCLUSION Strategies that increase the supply and transport of L-citrulline merit pursuit as novel approaches to managing infants with chronic, progressive pulmonary hypertension.
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Affiliation(s)
- Candice D. Fike
- Department of Pediatrics; Vanderbilt University Medical Center; Nashville TN USA
- Monroe Carell Jr. Children's Hospital at Vanderbilt; Nashville TN USA
| | - Marshall Summar
- Division of Genetics and Metabolism; Children's National Medical Center; Washington DC USA
| | - Judy L. Aschner
- Department of Pediatrics; Albert Einstein College of Medicine and the Children's Hospital at Montefiore; New York NY USA
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Soria LR, Marrone J, Molinas SM, Lehmann GL, Calamita G, Marinelli RA. Lipopolysaccharide impairs hepatocyte ureagenesis from ammonia: Involvement of mitochondrial aquaporin-8. FEBS Lett 2014; 588:1686-91. [DOI: 10.1016/j.febslet.2014.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 12/20/2022]
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Wijnands KAP, Vink H, Briedé JJ, van Faassen EE, Lamers WH, Buurman WA, Poeze M. Citrulline a more suitable substrate than arginine to restore NO production and the microcirculation during endotoxemia. PLoS One 2012; 7:e37439. [PMID: 22666356 PMCID: PMC3362574 DOI: 10.1371/journal.pone.0037439] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/23/2012] [Indexed: 12/15/2022] Open
Abstract
Background Impaired microcirculation during endotoxemia correlates with a disturbed arginine-nitric oxide (NO) metabolism and is associated with deteriorating organ function. Improving the organ perfusion in endotoxemia, as often seen in patients with severe infection or systemic inflammatory response syndrome (SIRS) is, therefore, an important therapeutic target. We hypothesized that supplementation of the arginine precursor citrulline rather than arginine would specifically increase eNOS-induced intracellular NO production and thereby improve the microcirculation during endotoxemia. Methodology/Principal Findings To study the effects of L-Citrulline and L-Arginine supplementation on jejunal microcirculation, intracellular arginine availability and NO production in a non-lethal prolonged endotoxemia model in mice. C57/Bl6 mice received an 18 hrs intravenous infusion of endotoxin (LPS, 0.4 µg•g bodyweight−1•h−1), combined with either L-Citrulline (6.25 mg•h-1), L-Arginine (6.25 mg•h−1), or L-Alanine (isonitrogenous control; 12.5 mg•h−1) during the last 6 hrs. The control group received an 18 hrs sterile saline infusion combined with L-Alanine or L-Citrulline during the last 6 hrs. The microcirculation was evaluated at the end of the infusion period using sidestream dark-field imaging of jejunal villi. Plasma and jejunal tissue amino-acid concentrations were measured by HPLC, NO tissue concentrations by electron-spin resonance spectroscopy and NOS protein concentrations using Western blot. Conclusion/Significance L-Citrulline supplementation during endotoxemia positively influenced the intestinal microvascular perfusion compared to L-Arginine-supplemented and control endotoxemic mice. L-Citrulline supplementation increased plasma and tissue concentrations of arginine and citrulline, and restored intracellular NO production in the intestine. L-Arginine supplementation did not increase the intracellular arginine availability. Jejunal tissues in the L-Citrulline-supplemented group showed, compared to the endotoxemic and L-Arginine-supplemented endotoxemic group, an increase in degree of phosphorylation of eNOS (Ser 1177) and a decrease in iNOS protein level. In conclusion, L-Citrulline supplementation during endotoxemia and not L-Arginine reduced intestinal microcirculatory dysfunction and increased intracellular NO production, likely via increased intracellular citrulline and arginine availability.
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Affiliation(s)
- Karolina A P Wijnands
- Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
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Siervo M, Stephan BCM, Feelisch M, Bluck LJC. Measurement of in vivo nitric oxide synthesis in humans using stable isotopic methods: a systematic review. Free Radic Biol Med 2011; 51:795-804. [PMID: 21672626 DOI: 10.1016/j.freeradbiomed.2011.05.032] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 04/22/2011] [Accepted: 05/25/2011] [Indexed: 11/16/2022]
Abstract
Stable isotopic methods are considered the "gold standard" for the measurement of rates of in vivo NO production. However, values reported for healthy human individuals differ by more than 1 order of magnitude. The reason for the apparent variability in NO production is unclear. The primary aim of this review was to evaluate and compare the rates of in vivo NO production in health and disease using stable isotope methods. Articles were retrieved using the PubMed electronic database. Information on concentrations, isotopic enrichments of fluxes, and conversion rates of molecules involved in the NO metabolic pathway was extracted from selected articles; 35 articles were included in the final analysis. Three protocols were identified, including the arginine-citrulline, the arginine-nitrate, and the oxygen-nitrate protocols. The arginine-citrulline protocol showed a wider variability compared to the arginine-nitrate and oxygen-nitrate protocols. The direction of the association between disease state and rate of NO production was essentially determined by the etiopathogenesis of the disorder (inflammatory, metabolic, vascular). Considerable variation in methodologies used to assess whole-body NO synthesis in humans exists. The precision of several aspects of the techniques and the validity of some assumptions made remain unknown, and there is a paucity of information about physiological rates of NO production from childhood over adolescence to old age.
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Affiliation(s)
- M Siervo
- Elsie Widdowson Laboratory, MRC Human Nutrition Research, Cambridge CB1 9NL, UK.
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Manto A, De Gennaro A, Serino A, Cozzolino A, Colasante AG, La Rocca MR. MRI in a woman with late onset ornithine transcarbamylase deficiency. Neuroradiol J 2010; 23:398-401. [PMID: 24148626 DOI: 10.1177/197140091002300403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 02/14/2010] [Indexed: 11/15/2022] Open
Abstract
We describe the brain MR imaging findings of a woman who developed neurologic symptoms due to an acute hyperammonemic encephalopathy resulting from late onset ornithine transcarbamylase deficiency (OCTD). MR images revealed injury (hyperintense foci on long TR images) to the subcortical white matter of the left precentral and supramarginal gyrus and in the left frontal lobe. These findings presumably reflect the distribution of brain injury from hypoperfusion secondary to severe hyperammonemia. If MR findings suggesting hypoperfusion are detected in a patient with hyperammonemia, the diagnosis of OCTD should be considered. Knowledge of the physiopathological mechanisms of OTCD and of MR imaging of hyperammonemic injury may help expedite diagnosis and treatment and prevent the exitus of patients with this genetic disorder.
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Affiliation(s)
- A Manto
- Neuroradiology Unit, Umberto I Hospital; Nocera Inferiore; Salerno, Italy -
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Delage B, Fennell DA, Nicholson L, McNeish I, Lemoine NR, Crook T, Szlosarek PW. Arginine deprivation and argininosuccinate synthetase expression in the treatment of cancer. Int J Cancer 2010; 126:2762-72. [PMID: 20104527 DOI: 10.1002/ijc.25202] [Citation(s) in RCA: 196] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Arginine, a semi-essential amino acid in humans, is critical for the growth of human cancers, particularly those marked by de novo chemoresistance and a poor clinical outcome. In addition to protein synthesis, arginine is involved in diverse aspects of tumour metabolism, including the synthesis of nitric oxide, polyamines, nucleotides, proline and glutamate. Tumoural downregulation of the enzyme argininosuccinate synthetase (ASS1), a recognised rate-limiting step in arginine synthesis, results in an intrinsic dependence on extracellular arginine due to an inability to synthesise arginine for growth. This dependence on extracellular arginine is known as arginine auxotrophy. Several tumours are arginine auxotrophic, due to variable loss of ASS1, including hepatocellular carcinoma, malignant melanoma, malignant pleural mesothelioma, prostate and renal cancer. Importantly, targeting extracellular arginine for degradation in the absence of ASS1 triggers apoptosis in arginine auxotrophs. Several phase I/II clinical trials of the arginine-lowering drug, pegylated arginine deiminase, have shown encouraging evidence of clinical benefit and low toxicity in patients with ASS1-negative tumours. In part, ASS1 loss is due to epigenetic silencing of the ASS1 promoter in various human cancer cell lines and tumours, and it is this silencing that confers arginine auxotrophy. In relapsed ovarian cancer, this is associated with platinum refractoriness. In contrast, several platinum sensitive tumours, including primary ovarian, stomach and colorectal cancer, are characterised by ASS1 overexpression, which is regulated by proinflammatory cytokines. This review examines the prospects for novel approaches in the prevention, diagnosis and treatment of malignant disease based on ASS1 pathophysiology and its rate-limiting product, arginine.
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Affiliation(s)
- Barbara Delage
- Queen Mary University of London, Centre for Molecular Oncology and Imaging, Institute of Cancer and CR-UK Clinical Centre, Barts and The London School of Medicine, Charterhouse Square, London, United Kingdom
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Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight recent publications examining nitric oxide production in health and disease and its association with clinical nutrition and alterations in metabolism. RECENT FINDINGS The role of the cofactor tetrahydrobiopterin in nitric oxide production and its relation with arginine availability is indicated as an important explanation for the arginine paradox. This offers potential for nitric oxide regulation by dietary factors such as arginine or its precursors and vitamin C. Because diets with a high saturated fat content induce high plasma fatty acid levels, endothelial nitric oxide production is often impaired due to a reduction in nitric oxide synthase 3 phosphorylation. Increasing the arginine availability by arginine therapy or arginase inhibition was, therefore, proposed as a potential therapy to treat hypertension. Recent studies in septic patients and transgenic mice models found that inadequate de-novo arginine production from citrulline reduces nitric oxide production. Citrulline supplementation may, therefore, be a novel therapeutic approach in conditions of arginine deficiency. SUMMARY Both lack and excess of nitric oxide production in diseases can have various important implications in which dietary factors can play a modulating role. Future research is needed to expand our understanding of the regulation and adequate measurement of nitric oxide production at the organ level and by the different nitric oxide synthase isoforms, also in relation to clinical nutrition.
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Affiliation(s)
- Yvette C Luiking
- Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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