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Chauvet L, Brunel A, Le Gouar Y, Guérin S, Janvier R, Henry G, Cahu A, Dupont D, Lemaire M, Le Huërou-Luron I, Deglaire A. Protein ingredient quality within infant formulas impacts plasma amino acid concentrations in neonatal minipiglets. J Nutr 2024:S0022-3166(24)00286-4. [PMID: 38801861 DOI: 10.1016/j.tjnut.2024.05.009] [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: 11/30/2023] [Revised: 03/13/2024] [Accepted: 05/13/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Infant formulas (IFs), the only adequate substitute to human milk, are complex matrices that require numerous ingredients and processing steps, which may impact protein digestion and subsequent amino acid absorption. OBJECTIVE The objective was to understand the impact of the protein ingredient quality within IFs on postprandial plasma amino acid (AA) profiles. METHODS Four isonitrogenous and isocaloric IFs were produced at a semi-industrial scale using whey proteins (WPs) from different origins (cheese vs. ideal whey) and denaturation levels (IFs-A/-B/-C), and caseins with different supramolecular organizations (IFs-C/-D). Ten Yucatan minipiglets (12- to 27-day-old) used as a human infant model, received each IF for 3 days according to a Williams Latin square, followed by a 2-day wash-out period. Jugular plasma was regularly sampled from 10 min preprandial to 4 h postprandial on the third day to measure free AAs, urea, insulin and glucose concentrations. Data were statistically analyzed using a mixed linear model with diet (IFs), time and gender as fixed factors and piglet as random factor. RESULTS IFs made with cheese whey (IFs-A and -B) elicited significantly higher plasma total and essential AA concentrations than IFs made with ideal whey (IF-C and -D), regardless of the pre- and post-prandial times. Most of the differences observed postprandially were explained by AA homeostasis modifications. IFs based on cheese whey induced an increased plasma concentration of Thr due to both a higher Thr content in these IFs and a Thr limiting degrading capability in piglets. The use of non-micellar casein ingredient led to reduced plasma content of AA catabolism markers (IF-D vs. IF-C). CONCLUSIONS Overall, our results highlight the importance of the protein ingredient quality (composition & structure) within IFs on the neonatal plasma AA profiles, which may impact further the infant protein metabolism.
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Affiliation(s)
- Lucile Chauvet
- STLO, INRAE, Institut Agro, Rennes, France;; Institut NuMeCan, INRAE, INSERM, Univ Rennes, Saint Gilles, France;; SODIAAL International, Centre Recherche & Innovation, Rennes, France
| | | | | | - Sylvie Guérin
- Institut NuMeCan, INRAE, INSERM, Univ Rennes, Saint Gilles, France
| | - Régis Janvier
- Institut NuMeCan, INRAE, INSERM, Univ Rennes, Saint Gilles, France
| | | | - Armelle Cahu
- Institut NuMeCan, INRAE, INSERM, Univ Rennes, Saint Gilles, France
| | | | - Marion Lemaire
- SODIAAL International, Centre Recherche & Innovation, Rennes, France
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Yang C, Chen H, Deng C, Sun N. Serological Exosome Metabolic Biopsy of Hepatocellular Carcinoma via Designed Core-Shell Nanoparticles. Anal Chem 2024. [PMID: 38323920 DOI: 10.1021/acs.analchem.3c02068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Exosome metabolite-based liquid biopsy is a promising strategy for large-scale application in practical clinics toward precise medicine. Given the current challenges in successive isolation and analysis of exosomes and their metabolites in this field, we established a low-cost, high-throughput, and rapid platform for serological exosome metabolic biopsy of hepatocellular carcinoma (HCC) via designed core-shell nanoparticles. It starts with the efficient extraction of high-quality serum exosomes and exosome metabolic features, based on which significantly obvious sample clusters are observed by unsupervised cluster analysis. The following integration of feature selection and supervised machine learning enables the identification of six key metabolites and achieves high-performance prediction between HCC, liver cirrhosis, and healthy controls. Specifically, both sensitivity and accuracy achieve 100% among any pairwise intergroup discrimination in a blind test. The quality and reliability of six key metabolites are further evaluated and validated by using different machine learning algorithms and pathway exploration. Our platform contributes to the future growth of new liquid biopsy technologies for precision diagnosis and real-time monitoring of HCC, among other conditions.
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Affiliation(s)
- Chenyu Yang
- Department of Chemistry, Institutes of Biomedical Sciences, Zhongshan Hospital, Fudan University, Shanghai 200433, China
| | - Haolin Chen
- Department of Chemistry, Institutes of Biomedical Sciences, Zhongshan Hospital, Fudan University, Shanghai 200433, China
| | - Chunhui Deng
- Department of Chemistry, Institutes of Biomedical Sciences, Zhongshan Hospital, Fudan University, Shanghai 200433, China
| | - Nianrong Sun
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Mok C, Levesque C, Urschel K. Evaluation of threonine requirements in mature horses fed 1:1 ratio of forage to concentrate using the indicator amino acid oxidation technique. Anim Feed Sci Technol 2021. [DOI: 10.1016/j.anifeedsci.2021.115133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Riederer M, Schweighofer N, Trajanoski S, Stelzer C, Zehentner M, Fuchs-Neuhold B, Kashofer K, Mayr JA, Hörmann-Wallner M, Holasek S, van der Kleyn M. Free threonine in human breast milk is related to infant intestinal microbiota composition. Amino Acids 2021; 54:365-383. [PMID: 34477981 PMCID: PMC8948153 DOI: 10.1007/s00726-021-03057-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/26/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Accumulating evidence indicates that free amino acids (FAA) might be bioactive compounds with potential immunomodulatory capabilities. However, the FAA composition in human milk is still poorly characterized with respect to its correlation to maternal serum levels and its physiological significance for the infant. Studies addressing the relation of human milk FAA to the infants' intestinal microbiota are still missing. METHODS As part of a pilot study, maternal serum and breast milk FAA concentrations as well as infant intestinal microbiota (16S rRNA) were determined 2 months after birth. The study cohort consisted of 41 healthy mothers and their term delivered, healthy infants with normal birthweight. The relationship between maternal serum and milk FAA was determined by correlation analyses. Associations between (highly correlated) milk FAA and infant intestinal beta diversity were tested using PERMANOVA, LefSe and multivariate regression models adjusted for common confounders. RESULTS Seven breast milk FAA correlated significantly with serum concentrations. One of these, threonine showed a negative association with abundance of members of the class Gammaproteobacteria (R2adj = 17.1%, p = 0.006; β= - 0.441). In addition, on the level of families and genera, threonine explained 23.2% of variation of the relative abundance of Enterobacteriaceae (R2adj; p = 0.001; β = - 0.504) and 11.1% of variability in the abundance of Escherichia/Shigella (R2adj, p = 0.025; β = - 0.368), when adjusted for confounders. CONCLUSION Our study is the first to suggest potential interactions between breast milk FAA and infant gut microbiota composition during early lactation. The results might be indicative of a potential protective role of threonine against members of the Enterobacteriaceae family in breast-fed infants. Still, results are based on correlation analyses and larger cohorts are needed to support the findings and elucidate possible underlying mechanisms to assess the complex interplay between breast milk FAA and infant intestinal microbiota in detail.
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Affiliation(s)
- Monika Riederer
- Institute of Biomedical Science, University of Applied Sciences JOANNEUM, Graz, Austria.
| | | | - Slave Trajanoski
- Core Facility Computational Bioanalytics, Center for Medical Research (ZMF), Medical University of Graz, Graz, Austria
| | - Claudia Stelzer
- Institute of Biomedical Science, University of Applied Sciences JOANNEUM, Graz, Austria
| | - Miriam Zehentner
- Institute of Biomedical Science, University of Applied Sciences JOANNEUM, Graz, Austria
| | - Bianca Fuchs-Neuhold
- Institute of Dietetics and Nutrition, Health Perception Lab, University of Applied Sciences JOANNEUM, Graz, Austria
| | - Karl Kashofer
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Auenbruggerpl. 2, 8036, Graz, Austria
| | - Johannes A Mayr
- Department of Pediatrics, Salzburger Landeskliniken and Paracelsus Medical University, Salzburg, Austria
| | - Marlies Hörmann-Wallner
- Institute of Dietetics and Nutrition, Health Perception Lab, University of Applied Sciences JOANNEUM, Graz, Austria
| | - Sandra Holasek
- Department of Pathophysiology, Medical University Graz, Graz, Austria
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Shama S, Unger S, Pouliot Y, Doyen A, Suwal S, Pencharz P, Pitino MA, Sergius M, Aufreiter S, Stone D, O'Connor DL. A Human Milk-Based Protein Concentrate Developed for Preterm Infants Retains Bioactive Proteins and Supports Growth of Weanling Rats. J Nutr 2021; 151:840-847. [PMID: 33693847 PMCID: PMC8030702 DOI: 10.1093/jn/nxaa383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/12/2020] [Accepted: 11/10/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Bovine milk-based protein modulars are currently available to nutrient-enrich enteral feedings; however, they have limitations for use in very-low-birth-weight infants. OBJECTIVES Our objectives were to develop a human milk-based protein (HMP) concentrate and to conduct a preclinical assessment of the HMP concentrate in weanling rats. METHODS An HMP concentrate was produced from donor milk using pressure-driven membrane filtration processes and high hydrostatic pressure processing. Protein and lactoferrin concentrations and lysozyme activity were determined by Kjeldahl, HPLC, and turbidimetric assay, respectively. Male Sprague Dawley rats 24 d old (n = 30) were randomly assigned to 1 of 3 isocaloric AIN-93G diets for 4 wk containing 100% casein (control) or with 50% of the casein replaced with the HMP concentrate (treatment) or a bovine whey protein isolate (treatment). Body weight, food intake, fat mass, plasma amino acid profiles, and organ weights were measured. Data were analyzed using linear regression models. RESULTS Raw donor milk contained (mean ± SD) 101 ± 6 g protein/kg and 5 ± 1 g lactoferrin/kg of milk solids. Postprocessing, protein and lactoferrin concentrations were 589 ± 3 g/kg and 29 ± 10 g/kg, respectively. Lysozyme activity was initially 209 ± 4 U/kg and increased to 959 ± 39 U/kg in the HMP concentrate. There were no statistically significant differences in body weight, food intake, fat mass, or plasma amino acid profiles between rats fed diets containing the HMP concentrate and the control diet. Full cecum weights were higher in rats fed the HMP concentrate than in those fed control diets (mean difference: 5.59 g; 95% CI: 4.50, 6.68 g; P < 0.0001), likely reflecting the concentration of human milk oligosaccharides. No differences were found for other organ weights. CONCLUSIONS The HMP concentrate retained important bioactive proteins and supported normal rat growth in the preclinical assessment.
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Affiliation(s)
- Sara Shama
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sharon Unger
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
- Department of Neonatology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada
- Rogers Hixon Ontario Human Milk Bank, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Yves Pouliot
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Science and Technology Research Centre (STELA), Laval University, Quebec City, Quebec, Canada
| | - Alain Doyen
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Science and Technology Research Centre (STELA), Laval University, Quebec City, Quebec, Canada
| | - Shyam Suwal
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Science and Technology Research Centre (STELA), Laval University, Quebec City, Quebec, Canada
| | - Paul Pencharz
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Michael A Pitino
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mélanie Sergius
- Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF), Dairy Science and Technology Research Centre (STELA), Laval University, Quebec City, Quebec, Canada
| | - Susanne Aufreiter
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Debbie Stone
- Rogers Hixon Ontario Human Milk Bank, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Deborah L O'Connor
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada
- Rogers Hixon Ontario Human Milk Bank, Mount Sinai Hospital, Toronto, Ontario, Canada
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Identification and Detection of Bioactive Peptides in Milk and Dairy Products: Remarks about Agro-Foods. Molecules 2020; 25:molecules25153328. [PMID: 32707993 PMCID: PMC7435915 DOI: 10.3390/molecules25153328] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Food-based components represent major sources of functional bioactive compounds. Milk is a rich source of multiple bioactive peptides that not only help to fulfill consumers 'nutritional requirements but also play a significant role in preventing several health disorders. Understanding the chemical composition of milk and its products is critical for producing consistent and high-quality dairy products and functional dairy ingredients. Over the last two decades, peptides have gained significant attention by scientific evidence for its beneficial health impacts besides their established nutrient value. Increasing awareness of essential milk proteins has facilitated the development of novel milk protein products that are progressively required for nutritional benefits. The need to better understand the beneficial effects of milk-protein derived peptides has, therefore, led to the development of analytical approaches for the isolation, separation and identification of bioactive peptides in complex dairy products. Continuous emphasis is on the biological function and nutritional characteristics of milk constituents using several powerful techniques, namely omics, model cell lines, gut microbiome analysis and imaging techniques. This review briefly describes the state-of-the-art approach of peptidomics and lipidomics profiling approaches for the identification and detection of milk-derived bioactive peptides while taking into account recent progress in their analysis and emphasizing the difficulty of analysis of these functional and endogenous peptides.
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Dunstan RH, Macdonald MM, Thorn B, Wood D, Roberts TK. Modelling of amino acid turnover in the horse during training and racing: A basis for developing a novel supplementation strategy. PLoS One 2020; 15:e0226988. [PMID: 31899789 PMCID: PMC6941815 DOI: 10.1371/journal.pone.0226988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/09/2019] [Indexed: 12/03/2022] Open
Abstract
Horses in heavy training in preparation for racing and competition have increased metabolic demands to support the more intensive levels of exercise and recovery. However, little is known at the metabolic level about amino acid turnover and the specific alterations of demand caused by high intensity exercise. During exercise, certain amino acids are required in greater quantities due to disproportionate losses via excretory systems and usage in biosynthetic pathways. This investigation has built a theoretical computer model in an attempt to bring together the published rates of protein intake and utilisation to try to understand how some amino acids might be in higher demand than others. The model indicated that after evaluation of the daily amino acid turnover, glutamine/glutamic acid (Glx), serine and ornithine were in negative nitrogen balance which identified these amino acids as critical limiting factors for anabolism. Adjustment of the modelling conditions to cater for high intensity training indicated that an additional demand was placed on eight amino acids, including GLx, valine, lysine, histidine and phenylalanine which could thus become limiting under these conditions. The modelling results indicated that an amino acid supplement with the correct amino acids to match demand could theoretically be beneficial to a 500Kg horse in quantities of 20-80g/day. These results open new avenues of research for specifically tailoring amino acid supplementation to meet demands for sports horses in heavy training and improving general well-being, especially in hotter climates.
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Affiliation(s)
- R. Hugh Dunstan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - Margaret M. Macdonald
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - Brittany Thorn
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - David Wood
- Horsepower Pty Ltd, Windsor, NSW, Australia
| | - Timothy K. Roberts
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
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8
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Modelling of protein turnover provides insight for metabolic demands on those specific amino acids utilised at disproportionately faster rates than other amino acids. Amino Acids 2019; 51:945-959. [PMID: 31028564 DOI: 10.1007/s00726-019-02734-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
The nitrogen balance is regulated by factors such as diet, physical activity, age, pathogenic challenges, and climatic conditions. A paradigm was developed from published recommended rates of protein intake (g/kg/day) with corresponding rates of endogenous protein turnover and excretion, to extrapolate amino acid balances under various conditions. The average proportions of amino acids in the ingested proteins representing a well-balanced diet were used to assess intake and an average human composition profile from five major high-turnover proteins in the body to assess endogenous protein turnover. The amino acid excretion profiles for urine and sweat were constructed for males and females from published data. The model calculated the nitrogen balances for a range of amino acids to determine the amino acid requirements to support daily exertion. Histidine, serine, glycine, and ornithine were in negative balances in males and females and this potential deficit was greater in the higher body-mass ranges. Conversely, leucine, isoleucine, and valine were conserved during nitrogen flux and resulted in positive balances. The model was run under a scenario of high demand for the synthesis of IgG during a response to an infectious challenge which indicated that these were increased requirements for tyrosine, threonine, and valine. It was concluded that these amino acids represent points of limitation to anabolic metabolism by restriction of their supply at critical times of demand. This would especially occur under conditions of fitness training, maintaining intensive exercise regimes, facilitating responses to pathogenic challenge, or recovery from injury.
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Lau CHE, Siskos AP, Maitre L, Robinson O, Athersuch TJ, Want EJ, Urquiza J, Casas M, Vafeiadi M, Roumeliotaki T, McEachan RRC, Azad R, Haug LS, Meltzer HM, Andrusaityte S, Petraviciene I, Grazuleviciene R, Thomsen C, Wright J, Slama R, Chatzi L, Vrijheid M, Keun HC, Coen M. Determinants of the urinary and serum metabolome in children from six European populations. BMC Med 2018; 16:202. [PMID: 30404627 PMCID: PMC6223046 DOI: 10.1186/s12916-018-1190-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/10/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Environment and diet in early life can affect development and health throughout the life course. Metabolic phenotyping of urine and serum represents a complementary systems-wide approach to elucidate environment-health interactions. However, large-scale metabolome studies in children combining analyses of these biological fluids are lacking. Here, we sought to characterise the major determinants of the child metabolome and to define metabolite associations with age, sex, BMI and dietary habits in European children, by exploiting a unique biobank established as part of the Human Early-Life Exposome project ( http://www.projecthelix.eu ). METHODS Metabolic phenotypes of matched urine and serum samples from 1192 children (aged 6-11) recruited from birth cohorts in six European countries were measured using high-throughput 1H nuclear magnetic resonance (NMR) spectroscopy and a targeted LC-MS/MS metabolomic assay (Biocrates AbsoluteIDQ p180 kit). RESULTS We identified both urinary and serum creatinine to be positively associated with age. Metabolic associations to BMI z-score included a novel association with urinary 4-deoxyerythreonic acid in addition to valine, serum carnitine, short-chain acylcarnitines (C3, C5), glutamate, BCAAs, lysophosphatidylcholines (lysoPC a C14:0, lysoPC a C16:1, lysoPC a C18:1, lysoPC a C18:2) and sphingolipids (SM C16:0, SM C16:1, SM C18:1). Dietary-metabolite associations included urinary creatine and serum phosphatidylcholines (4) with meat intake, serum phosphatidylcholines (12) with fish, urinary hippurate with vegetables, and urinary proline betaine and hippurate with fruit intake. Population-specific variance (age, sex, BMI, ethnicity, dietary and country of origin) was better captured in the serum than in the urine profile; these factors explained a median of 9.0% variance amongst serum metabolites versus a median of 5.1% amongst urinary metabolites. Metabolic pathway correlations were identified, and concentrations of corresponding metabolites were significantly correlated (r > 0.18) between urine and serum. CONCLUSIONS We have established a pan-European reference metabolome for urine and serum of healthy children and gathered critical resources not previously available for future investigations into the influence of the metabolome on child health. The six European cohort populations studied share common metabolic associations with age, sex, BMI z-score and main dietary habits. Furthermore, we have identified a novel metabolic association between threonine catabolism and BMI of children.
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Affiliation(s)
- Chung-Ho E Lau
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.
| | - Alexandros P Siskos
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.,Division of Cancer, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Léa Maitre
- ISGlobal, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,CIBER Epidemiologa y Salud Pública (CIBERESP), Madrid, Spain
| | - Oliver Robinson
- MRC-PHE Centre for Environment and Health, School of Public Health, Faculty of Medicine, Imperial College London, London, W2 1PG, UK
| | - Toby J Athersuch
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.,MRC-PHE Centre for Environment and Health, School of Public Health, Faculty of Medicine, Imperial College London, London, W2 1PG, UK
| | - Elizabeth J Want
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Jose Urquiza
- ISGlobal, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,CIBER Epidemiologa y Salud Pública (CIBERESP), Madrid, Spain
| | - Maribel Casas
- ISGlobal, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,CIBER Epidemiologa y Salud Pública (CIBERESP), Madrid, Spain
| | - Marina Vafeiadi
- Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Theano Roumeliotaki
- Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Rosemary R C McEachan
- Bradford Institute for Health Research, Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK
| | - Rafaq Azad
- Bradford Institute for Health Research, Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK
| | - Line S Haug
- Norwegian Institute of Public Health, Oslo, Norway
| | | | - Sandra Andrusaityte
- Department of Environmental Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | - Inga Petraviciene
- Department of Environmental Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | | | | | - John Wright
- Bradford Institute for Health Research, Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK
| | - Remy Slama
- Inserm, Univ. Grenoble Alpes, CNRS, IAB (Institute of Advanced Biosciences), Grenoble, France
| | - Leda Chatzi
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, USA
| | - Martine Vrijheid
- ISGlobal, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,CIBER Epidemiologa y Salud Pública (CIBERESP), Madrid, Spain
| | - Hector C Keun
- Division of Cancer, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Muireann Coen
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK. .,Oncology Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, 1 Francis Crick Avenue, Cambridge, CB2 0RE, UK.
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Mok CH, Levesque CL, Urschel KL. Using the indicator amino acid oxidation technique to study threonine requirements in horses receiving a predominantly forage diet. J Anim Physiol Anim Nutr (Berl) 2018; 102:1366-1381. [PMID: 29901867 DOI: 10.1111/jpn.12927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 04/16/2018] [Accepted: 05/07/2018] [Indexed: 01/29/2023]
Abstract
Threonine has been reported to be the second limiting amino acid in typical equine diets, but its actual requirement has not been determined in horses. To evaluate amino acid metabolism and requirements, the indicator amino acid oxidation (IAAO) method has been successfully used in other species. The objective of this research was to estimate threonine requirements in mature horses fed timothy hay and concentrate in 4:1 ratio using the IAAO method. Six Thoroughbred mares (579.9 ± 46.7 kg) received each of 6 levels of threonine intake, 41, 51, 61, 70, 80 and 89 mg/kg BW/day, in a randomly determined order. Each study period was 7-day long, and on day 6, blood samples were collected before and 90 min after feeding to measure amino acid concentrations using HPLC. On day 7, horses underwent IAAO procedures, which included a 2-hr primed, constant intravenous infusion of [13 C]sodium bicarbonate to measure total CO2 production and a 4-hr primed, constant oral administration of [1-13 C]phenylalanine to estimate phenylalanine oxidation to CO2 . Blood and breath samples were collected to measure blood [13 C]phenylalanine, using GC-MS analysis and breath 13 CO2 enrichment, using an infrared isotope analyser. Increasing threonine intake levels did not affect plasma phenylalanine oxidation by the ANOVA test (p > 0.05) but resulted in a linear decrease in phenylalanine oxidation (p = 0.04) without a breakpoint by the orthogonal linear contrast. This study is the first attempt to evaluate threonine requirements in horses by the IAAO method; however, threonine requirements are still unknown in mature horses at this time.
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Affiliation(s)
- Chan Hee Mok
- Department of Animal and Food Sciences, University of Kentucky, Lexington, Kentucky
| | - Crystal L Levesque
- Department of Animal Science, South Dakota State University, Brookings, South Dakota
| | - Kristine L Urschel
- Department of Animal and Food Sciences, University of Kentucky, Lexington, Kentucky
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11
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Morgan C, Burgess L. High Protein Intake Does Not Prevent Low Plasma Levels of Conditionally Essential Amino Acids in Very Preterm Infants Receiving Parenteral Nutrition. JPEN J Parenter Enteral Nutr 2016; 41:455-462. [PMID: 26150412 DOI: 10.1177/0148607115594009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND We have shown that increasing protein intake using a standardized, concentrated, added macronutrients parenteral (SCAMP) nutrition regimen improves head growth in very preterm infants (VPIs) compared with a control parenteral nutrition (PN) regimen. VPIs are at risk of conditionally essential amino acid (CEAA) deficiencies because of current neonatal PN amino acid (AA) formulations. We hypothesized that the SCAMP regimen would prevent low plasma levels of CEAAs. AIM To compare the plasma AA profiles at approximately day 9 of life in VPIs receiving SCAMP vs a control PN regimen. METHODS VPIs (<29 weeks' gestation) were randomized to receive SCAMP (30% more PN AA) or a control regimen. Data were collected to measure parenteral and enteral protein, energy, and individual AA intake and the first plasma AA profile. Plasma profiles of the 20 individual protogenic AA levels were measured using ion exchange chromatography. RESULTS Plasma AA profiles were obtained at median (interquartile range [IQR]) age of 9 (8-10) days in both SCAMP (n = 59) and control (n = 67) groups after randomizing 150 VPIs. Median (IQR) plasma levels of individual essential AAs were higher than the reference population mean (RPM) in both groups, especially for threonine. SCAMP infants had higher plasma levels of essential AAs than did the controls. Median (IQR) plasma levels of glutamine, arginine, and cysteine (CEAAs) were lower than the RPM in both groups. CONCLUSION Plasma AA levels in PN-dependent VPIs indicate there is an imbalance in essential and CEAA provision in neonatal PN AA formulations that is not improved by increasing protein intake.
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Affiliation(s)
- Colin Morgan
- 1 Department of Neonatology, Liverpool Women's Hospital, Liverpool, UK
| | - Laura Burgess
- 1 Department of Neonatology, Liverpool Women's Hospital, Liverpool, UK
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Li W, Sun K, Ji Y, Wu Z, Wang W, Dai Z, Wu G. Glycine Regulates Expression and Distribution of Claudin-7 and ZO-3 Proteins in Intestinal Porcine Epithelial Cells. J Nutr 2016; 146:964-9. [PMID: 27029941 DOI: 10.3945/jn.115.228312] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/16/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Glycine traditionally is classified as a nutritionally nonessential amino acid in humans and animals. Because of its abundance in the body and its extensive use via multiple pathways, requirements for glycine are particularly high in neonates. Our recent studies show that dietary glycine supplementation is needed for optimal intestinal development in piglets. Importantly, reduced concentrations of glycine in the lumen of the small intestine are associated with gut dysfunction in low-birth-weight piglets. However, the mechanisms responsible for the beneficial effects of glycine on the intestinal mucosal barrier are largely unknown. OBJECTIVE This study tested the hypothesis that glycine may regulate the expression and distribution of tight junction (TJ) proteins, thereby contributing to intestinal mucosal barrier function. METHODS Enterocytes isolated from the jejunum of a healthy newborn pig were propagated to establish a stable cell line. The cells were cultured with 0.05 mmol glycine/L (control; concentration in the small intestinal lumen of low-birth-weight piglets) or 0.25 or 1.0 mmol glycine/L for the indicated periods of time. Epithelial barrier integrity and expression and localization of TJ proteins were analyzed by using monolayer transepithelial electrical resistance (TEER) and paracellular permeability, Western blot, and immunofluorescence imaging. RESULTS Compared with controls, cells cultured with 0.25 or 1.0 mmol glycine/L increased TEER (P < 0.05) by 46-53% and 80-111%, respectively, at 60-72 h. Correspondingly, paracellular permeability was reduced (P < 0.05) by 6-21% and 18-27% for 0.25 or 1.0 mmol glycine/L treatment, respectively, at 36-72 h. Compared with controls, protein abundances for claudin-3, claudin-7, and zonula occludens (ZO) 3 were enhanced (25-33%, P < 0.05) by 0.25 and 1.0 mmol glycine/L at 8 h, whereas those for occludin, claudin-1, claudin-4, and ZO-2 were not affected. Compared with controls, 1.0 mmol glycine/L reduced the protein abundance of ZO-1 by 20% at 8 h (P < 0.05), but 0.25 mmol glycine/L had no effect. A glycine concentration of 0.25 mmol/L sustained the localization of claudin-7 and ZO-3 to the interface between enterocytes. Interestingly, 1 mmol glycine/L promoted the distribution of claudin-4 and claudin-7 to the cytosol and nucleus, and the localization of ZO-3 to the plasma membranes, while decreasing the distribution of ZO-1 at cell-cell contact sites, compared with control cells. CONCLUSION Physiologic concentrations of glycine support intestinal mucosal barrier function by regulating the abundance and distribution of claudin-7 and ZO-3 in enterocytes. Supplementation with glycine may provide an effective nutritional strategy to improve intestinal integrity in piglets.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Kaiji Sun
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Yun Ji
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Weiwei Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Zhaolai Dai
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and
| | - Guoyao Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and Department of Animal Science, Texas A&M University, College Station, TX
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13
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Abstract
OBJECTIVE Threonine is one of the essential amino acids. Its major fate is incorporation into intestinal mucosal proteins and synthesis of secretory glycoproteins. Therefore, it has an important function in the neonatal gut barrier integrity. The objective was to quantify the threonine requirement in fully enterally fed term neonates by means of the indicator amino acid oxidation (IAAO) method, using L-[1-C]phenylalanine as indicator. METHODS After a 24-hour test diet adaptation, containing randomly assigned amounts of threonine (range 5-182 mg · kg · day), the participating neonates received a primed continuous infusion of [C]bicarbonate and L-[1-C]phenylalanine. At baseline and during the plateau phase of both infusions, breath samples were obtained for CO2. The fractional L-[1-C]phenylalanine oxidation (FCO2) was estimated and plotted against the threonine intakes. Biphasic linear regression crossover analysis was used to calculate the breakpoint of the FCO2, representing the mean threonine requirement. Data are presented as mean ± SD. RESULTS Thirty-two term neonates (gestational age 39 ± 1 weeks, birth weight 3.3 ± 0.3 kg, mean postnatal age 10 ± 4 days) were studied. The mean threonine requirement was estimated to be 68 mg · kg · day with an upper and lower 95% confidence interval of 104 and 32 mg · kg · day, respectively (r = 0.37). CONCLUSIONS The determined threonine requirement is extremely close to the existing requirement recommendations (∼90% of the present World Health Organization requirement guidelines). Infant formula preparations presently on the market, however, contain up to twice as much threonine as recommended. The threonine intake in formula-fed infants may therefore be reduced considerably.
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Hong Y, Jiang W, Kuang S, Hu K, Tang L, Liu Y, Jiang J, Zhang Y, Zhou X, Feng L. Growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp Ctenopharyngodonidella fed graded levels of dietary threonine. J Anim Sci Biotechnol 2015; 6:34. [PMID: 26257911 PMCID: PMC4529687 DOI: 10.1186/s40104-015-0032-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 07/02/2015] [Indexed: 02/01/2023] Open
Abstract
Background This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp (Ctenopharyngodonidella). Results Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine (P < 0.05). Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation (P < 0.05). Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine (P < 0.05). Conclusions Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp (441.9-1,013.4 g) based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.
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Affiliation(s)
- Yang Hong
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Weidan Jiang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Shengyao Kuang
- Sichuan Academy of Animal Science, Animal Nutrition Institute, Chengdu, 610066 China
| | - Kai Hu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Ling Tang
- Sichuan Academy of Animal Science, Animal Nutrition Institute, Chengdu, 610066 China
| | - Yang Liu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Jun Jiang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Yongan Zhang
- Chinese Academy of Sciences, Institute of Hydrobiology, Wuhan, 430072 China
| | - Xiaoqiu Zhou
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Lin Feng
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130 Sichuan China ; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
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Abstract
Preterm infants provided with sufficient nutrition to achieve intrauterine growth rates have the greatest potential for optimal neurodevelopment. Although human milk is the preferred feeding for preterm infants, unfortified human milk provides insufficient nutrition for the very low-birth-weight infant. Even after fortification with human milk fortifier, human milk often fails to meet the high protein needs of the smallest preterm infants, and additional protein supplementation must be provided. Although substantial evidence exists to support quantitative protein goals for human milk-fed preterm infants, the optimal type of protein for use in human milk fortification remains uncertain. This question was addressed through a PubMed literature search of prospective clinical trials conducted since 1990 in preterm or low-birth-weight infant populations. The following 3 different aspects of protein quality were evaluated: whey-to-casein ratio, hydrolyzed versus intact protein, and bovine milk protein versus human milk protein. Because of a scarcity of current studies conducted with fortified human milk, studies examining protein quality using preterm infant formulas were included to address certain components of the clinical question. Twenty-six studies were included in the review study. No definite advantage was found for any specific whey-to-casein ratio. Protein hydrolyzate products with appropriate formulations can support adequate growth and biochemical indicators of nutrition status and may reduce gastrointestinal transit time, gastroesophageal reflux events, and later incidence of atopic dermatitis in some infants. Plasma amino acid levels similar to those of infants fed exclusive human milk-based diets can be achieved with products composed of a mixture of bovine proteins, peptides, and amino acids formulated to replicate the amino acid composition of human milk. Growth and biochemical indicators of nutrition status are similar for infants fed human milk fortified with human milk protein and bovine milk protein.
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Zhang Y, Dai Z, Wu G, Zhang R, Dai Y, Li N. Expression of threonine-biosynthetic genes in mammalian cells and transgenic mice. Amino Acids 2014; 46:2177-88. [PMID: 24893662 DOI: 10.1007/s00726-014-1769-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 05/21/2014] [Indexed: 12/16/2022]
Abstract
Threonine is a nutritionally essential amino acid (EAA) for the growth and development of humans and other nonruminant animals and must be provided in diets to sustain life. The aim of this study was to synthesize threonine in mammalian cells through transgenic techniques. To achieve this goal, we combined the genes involved in bacterial threonine biosynthesis pathways into a single open reading frame separated by self-cleaving peptides (2A) and then linked it into a transposon system (piggyBac). The plasmids pEF1a-IRES-GFP-E2F-his and pEF1a-IRES-GFP-M2F-his expressed Escherichia coli homoserine kinase and threonine synthase efficiently in mouse cells and enabled cells to synthesize threonine from homoserine. This biosynthetic pathway occurred with a low level of efficiency in transgenic mice. Three transgenic mice were identified by Southern blot from 72 newborn mice, raising the possibility that a high level of expression of these genes in mouse embryos might be lethal. The results indicated that it is feasible to synthesize threonine in animal cells using genetic engineering technology. Further work is required to improve the efficiency of this method for introducing genes into mammals. We propose that the transgenic technology provides a promising means to enhance the synthesis of nutritionally EAAs in farm animals and to eliminate or reduce supplementation of these nutrients in diets for livestock, poultry and fish.
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Affiliation(s)
- Yurui Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
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Zhang Z, Adelman AS, Rai D, Boettcher J, Lőnnerdal B. Amino acid profiles in term and preterm human milk through lactation: a systematic review. Nutrients 2013; 5:4800-21. [PMID: 24288022 PMCID: PMC3875913 DOI: 10.3390/nu5124800] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 10/28/2013] [Accepted: 10/31/2013] [Indexed: 01/04/2023] Open
Abstract
Amino acid profile is a key aspect of human milk (HM) protein quality. We report a systematic review of total amino acid (TAA) and free amino acid (FAA) profiles, in term and preterm HM derived from 13 and 19 countries, respectively. Of the 83 studies that were critically reviewed, 26 studies with 3774 subjects were summarized for TAA profiles, while 22 studies with 4747 subjects were reviewed for FAA. Effects of gestational age, lactation stage, and geographical region were analyzed by Analysis of Variance. Data on total nitrogen (TN) and TAA composition revealed general inter-study consistency, whereas FAA concentrations varied among studies. TN and all TAA declined in the first two months of lactation and then remained relatively unchanged. In contrast, the FAA glutamic acid and glutamine increased, peaked around three to six months, and then declined. Some significant differences were observed for TAA and FAA, based on gestational age and region. Most regional TAA and FAA data were derived from Asia and Europe, while information from Africa was scant. This systematic review represents a useful evaluation of the amino acid composition of human milk, which is valuable for the assessment of protein quality of breast milk substitutes.
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Affiliation(s)
- Zhiying Zhang
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; E-Mail:
| | - Alicia S. Adelman
- Mead Johnson Pediatric Nutrition Institute, Evansville, IN 47721, USA; E-Mails: (A.S.A.); (D.R.)
| | - Deshanie Rai
- Mead Johnson Pediatric Nutrition Institute, Evansville, IN 47721, USA; E-Mails: (A.S.A.); (D.R.)
| | - Julia Boettcher
- Mead Johnson Pediatric Nutrition Institute, Evansville, IN 47721, USA; E-Mails: (A.S.A.); (D.R.)
| | - Bo Lőnnerdal
- Department of Nutrition, University of California, Davis, CA 95616, USA; E-Mail:
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de Groof F, Huang L, Twisk JWR, Voortman GJ, Joemai W, Hau CH, Schierbeek H, Chen C, Huang Y, van Goudoever JB. New insights into the methodological issues of the indicator amino acid oxidation method in preterm neonates. Pediatr Res 2013; 73:679-84. [PMID: 23407117 DOI: 10.1038/pr.2013.31] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND We determined the effect of adaptation to the study diet on oxidation of the indicator amino acid and the required tracer washout time in preterms. METHODS Subjects received a study diet for 6 d that entailed a 50% reduction in leucine. Tracer studies using enterally infused [(13)C]bicarbonate and [1-(13)C]phenylalanine were performed on days 1, 2, 4, and 6. Breath samples containing (13)CO2 were collected during steady state and measured by infrared spectrometric analysis, and the fraction of (13)CO2 recovery from (13)C oxidation (F(13)CO2) was calculated. RESULTS Preterm infants (n = 11, birth weight 1.9 ± 0.1 kg, gestational age 32.6 ± 1.5 wk) received 166 mg/kg/d of leucine. Baseline enrichment changed significantly at day 1 of the study diet. F(13)CO2 did not change significantly between days 2 and 4 but was significantly lower at day 6. The tracer washout time was determined to be 7.5 h using a biphasic regression analysis. CONCLUSION One day of adaptation to a new diet is necessary to adapt to the (13)C enrichment of the study formula before starting infant requirement studies. Adaptation for a period of 5 d results in a protein-sparing response. The minimal time between two studies within the same subject is 7.5 h.
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Affiliation(s)
- Femke de Groof
- Division of Neonatology, Department of Pediatrics, Erasmus Medical Center, Sophia Children's Hospital Rotterdam, Rotterdam, The Netherlands
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Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids 2013; 45:463-77. [PMID: 23615880 DOI: 10.1007/s00726-013-1493-1] [Citation(s) in RCA: 432] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 01/01/2023]
Abstract
Glycine is a major amino acid in mammals and other animals. It is synthesized from serine, threonine, choline, and hydroxyproline via inter-organ metabolism involving primarily the liver and kidneys. Under normal feeding conditions, glycine is not adequately synthesized in birds or in other animals, particularly in a diseased state. Glycine degradation occurs through three pathways: the glycine cleavage system (GCS), serine hydroxymethyltransferase, and conversion to glyoxylate by peroxisomal D-amino acid oxidase. Among these pathways, GCS is the major enzyme to initiate glycine degradation to form ammonia and CO2 in animals. In addition, glycine is utilized for the biosynthesis of glutathione, heme, creatine, nucleic acids, and uric acid. Furthermore, glycine is a significant component of bile acids secreted into the lumen of the small intestine that is necessary for the digestion of dietary fat and the absorption of long-chain fatty acids. Glycine plays an important role in metabolic regulation, anti-oxidative reactions, and neurological function. Thus, this nutrient has been used to: (1) prevent tissue injury; (2) enhance anti-oxidative capacity; (3) promote protein synthesis and wound healing; (4) improve immunity; and (5) treat metabolic disorders in obesity, diabetes, cardiovascular disease, ischemia-reperfusion injuries, cancers, and various inflammatory diseases. These multiple beneficial effects of glycine, coupled with its insufficient de novo synthesis, support the notion that it is a conditionally essential and also a functional amino acid for mammals (including pigs and humans).
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Vandenplas Y, Plaskie K, Hauser B. Safety and adequacy of a semi-elemental formula for children with gastro-intestinal disease. Amino Acids 2009; 38:909-14. [PMID: 19408097 PMCID: PMC2839472 DOI: 10.1007/s00726-009-0298-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 04/17/2009] [Indexed: 11/04/2022]
Abstract
A prospective, open trial was conducted to evaluate the nutritional adequacy of a semi-elemental diet in 47 children with functional gastro-intestinal disorders. Nutritional adequacy was assessed based on growth relative to Euro-growth standards for body mass index (BMI)-for-age z-scores and evaluations of blood parameters. Twenty-five patients completed the study. In total, 533 l of “New-Alfare” was consumed during 775 trial-days. The mean intake per infant was 85.8 ± 26.8 kcal/kg/day or 122.5 ± 38.3 ml/kg/day. Weight and length evolution during the 4 weeks trial were within normal range. The mean BMI-for-age z-score (P < 0.05) and albumin concentration (P < 0.01) increased significantly after 4 weeks. Plasma threonine concentration decreased significantly (P = 0.01) and the tryptophan concentration increased (P = 0.06). No adverse events related to the study formula were reported. These results show that “New Alfaré” is safe and nutritionally adequate for pediatric patients with gastro-intestinal disease.
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Affiliation(s)
- Yvan Vandenplas
- Department of Pediatrics, Universitair Ziekenhuis Brussel Kinderen, Laarbeeklaan 101, 1090 Brussels, Belgium.
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21
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Chapman KP, Courtney-Martin G, Moore AM, Ball RO, Pencharz PB. Threonine requirement of parenterally fed postsurgical human neonates. Am J Clin Nutr 2009; 89:134-41. [PMID: 19056607 DOI: 10.3945/ajcn.2008.26654] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The threonine requirement of human neonates who receive parenteral nutrition (PN) has not been determined experimentally. OBJECTIVE The objective was to determine the parenteral threonine requirement for human neonates by using the minimally invasive indicator amino acid oxidation technique with L-[1-(13)C]phenylalanine as the indicator amino acid. DESIGN Nine postsurgical neonates were randomly assigned to 16 threonine intakes ranging from 10 to 100 mg . kg(-1) . d(-1). Breath and urine samples were collected at baseline and at plateau for (13)CO(2) and amino acid enrichment, respectively. The mean threonine requirement was determined by applying a 2-phase linear regression crossover analysis to the measured rates of (13)CO(2) release (F(13)CO(2)) and L-[1-(13)C]phenylalanine oxidation. RESULTS The mean threonine parenteral requirement determined by using phenylalanine oxidation was 37.6 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.9 and 45.2 mg . kg(-1) . d(-1)) and by using F(13)CO(2) oxidation was 32.8 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.7 and 35.9 mg . kg(-1) . d(-1)). Graded intakes of threonine had no effect on phenylalanine flux. CONCLUSION This is the first study to report on the threonine requirement for human neonates receiving PN. We found that the threonine requirement for postsurgical PN-fed neonates is 22-32% of the content of threonine that is presently found in commercial PN solutions (111-165 mg . kg(-1) . d(-1)).
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Affiliation(s)
- Karen P Chapman
- Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
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Pencharz PB, Elango R, Ball RO. An approach to defining the upper safe limits of amino acid intake. J Nutr 2008; 138:1996S-2002S. [PMID: 18806114 DOI: 10.1093/jn/138.10.1996s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The existing data on the safe upper limits of amino acid intake in humans is essentially observational; how much do individuals ingest and what side effects do they have? There are numerous studies in humans comparing the effects of high doses of amino acids given as protein bound vs. as free amino acids. These studies have shown that protein-bound amino acids have much less effect on plasma levels of the test amino acid, because protein intake stimulates protein synthesis as another sink for the increased amino acid intake. In practice, the highest amino acid intakes occur with free amino acid supplements that may be ingested by athletes who believe that the amino acids will benefit them in training and/or performance. Previously, in a piglet study, we were able to define the point at which maximal phenylalanine oxidation occurred, above which plasma phenylalanine concentration and body balance rose exponentially. We regard this value of maximal disposal (oxidation) of an amino acid as one metabolic marker of the upper limit of intake. Recently, others have demonstrated a similar maximal oxidation rate for leucine in rats. Based on these experimental data and the paucity of published human data in controlled experiments, we think that a systematic approach needs to be undertaken to define the maximal oxidation rate for all dietary indispensable amino acids and other amino acids that may be ingested in excess by humans. We believe that this will provide a rational basis to begin to define the upper limits of tolerance for dietary amino acids. However, some amino acids, such as threonine and methionine, will be more difficult to study, because they have more than 1 route of disposal or very complex metabolic regulation, in which case defining their upper limits will be more multifaceted.
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Affiliation(s)
- Paul B Pencharz
- Research Institute, Hospital for Sick Children, M5G 1X8 Toronto, Ontario, Canada.
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Sandström O, Lönnerdal B, Graverholt G, Hernell O. Effects of alpha-lactalbumin-enriched formula containing different concentrations of glycomacropeptide on infant nutrition. Am J Clin Nutr 2008; 87:921-8. [PMID: 18400715 DOI: 10.1093/ajcn/87.4.921] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Formula-fed infants have growth and plasma amino acid patterns different from those of breastfed infants. OBJECTIVE alpha-Lactalbumin is a major protein in human milk, and the addition of bovine alpha-lactalbumin to infant formula has been proposed to modify the plasma amino acid pattern of the recipient infant, possibly allowing a reduction in the protein content of the formula, which may affect growth. DESIGN We compared breastfed infants and infants fed standard formula or alpha-lactalbumin-enriched formulas (25% of protein) with glycomacropeptide accounting for 15% or 10% of the protein. The protein content of each formula was 13.1 g/L. Ninety-six infants aged 6 +/- 2 wk were recruited. Anthropometric measures were recorded, and interviews were conducted at enrollment and monthly until 6 mo of age. Blood samples were collected at enrollment and at 4 and 6 mo. RESULTS Formula intake did not differ between groups, and weight gain in the alpha-lactalbumin-enriched formula groups were similar to that of the breastfed infants. The standard formula group gained significantly more weight than did the breastfed infants. All formula-fed infants had significantly higher plasma concentrations of most essential amino acids at 4 and 6 mo than did the breastfed infants, and serum urea nitrogen was also higher in the formula-fed infants. Insulin and leptin concentrations did not differ between groups. CONCLUSIONS Compared with standard formula-fed infants, infants fed formula with a modified protein composition had growth patterns more similar to those of breastfed infants. All formula-fed groups had plasma amino acid concentrations similar to or higher than those of breastfed infants. This indicates that the protein content of alpha-lactalbumin-enriched formula can be further reduced, which should be evaluated.
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Affiliation(s)
- Olof Sandström
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden
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Ney DM, Hull AK, van Calcar SC, Liu X, Etzel MR. Dietary glycomacropeptide supports growth and reduces the concentrations of phenylalanine in plasma and brain in a murine model of phenylketonuria. J Nutr 2008; 138:316-22. [PMID: 18203898 DOI: 10.1093/jn/138.2.316] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Phenylketonuria (PKU) is a genetic disorder caused by deficiency of phenylalanine hydroxylase (PAH) that requires life-long adherence to a low-phenylalanine (Phe) diet. Glycomacropeptide (GMP) is uniquely suited to the nutritional management of PKU, because pure GMP contains no Phe. Our aim was to assess how ingestion of diets containing GMP support growth and affect the concentrations of amino acids in plasma and brains of mice with a deficiency of PAH, the Pah(enu2) mouse (PKU mouse). Experiments were conducted in 4- to 6-wk-old wild-type (WT) (C57Bl/6) and PKU mice fed diets containing 20% protein from casein, amino acids, or GMP supplemented with limiting indispensable amino acids (IAA). PKU mice fed the GMP diet showed gains in body weight, feed efficiency, and a protein efficiency ratio that did not differ from the amino acid diet. The concentrations of isoleucine and threonine in plasma showed a significant 2- to 3-fold increase for WT and PKU mice fed GMP compared with casein or amino acid diets, respectively. PKU mice fed the GMP diet had decreased concentrations of Phe in plasma (11% decrease) and in 5 regions of the brain (20% decrease) compared with the amino acid diet. The concentration of Phe in the brain was inversely correlated with the concentrations of isoleucine, threonine, and valine in plasma (R2 = 0.74; P < 0.0001), suggesting competitive inhibition of Phe transport into the brain. In summary, PKU mice fed GMP showed comparable growth and reduced concentrations of Phe in plasma and the brain compared with an amino acid diet. These data support the use of GMP supplemented with IAA as an alternative source of dietary protein for individuals with PKU.
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Affiliation(s)
- Denise M Ney
- Department of Nutritional Sciences, University of Wisconsin, Madison, WI 53706, USA.
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van der Schoor SRD, Wattimena DL, Huijmans J, Vermes A, van Goudoever JB. The gut takes nearly all: threonine kinetics in infants. Am J Clin Nutr 2007; 86:1132-8. [PMID: 17921393 DOI: 10.1093/ajcn/86.4.1132] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Threonine is an essential amino acid that is abundantly present in intestinally produced glycoproteins. Animal studies show that intestinal first-pass threonine metabolism is high, particularly during a restricted enteral protein intake. OBJECTIVE The objective of the study was to quantify intestinal first-pass threonine metabolism in preterm infants during full enteral feeding and during restricted enteral intake. DESIGN Eight preterm infants (x +/- SD birth weight: 1.1 +/- 0.1 kg; gestational age: 29 +/- 2 wk) were studied during 2 periods. During period A, 40% of total intake was administered enterally and 60% was administered parenterally. Total threonine intake was 58 +/- 6 micromol kg(-1) h(-1). During period B, the infants received full enteral feeding, and the total threonine intake was 63 +/- 6 micromol kg(-1) h(-1). Dual stable-isotope tracer techniques were used to assess splanchnic and whole-body threonine kinetics. RESULTS The fractional first-pass threonine uptake by the intestine was remarkably high in both periods: 82 +/- 6% during partial enteral feeding and 70 +/- 6% during full enteral feeding. Net threonine retention was not affected by the route of feeding. CONCLUSION In preterm infants, the splanchnic tissues extract a very large amount of the dietary threonine intake, which indicates a high obligatory visceral need for threonine, presumably for the purposes of synthesis.
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Affiliation(s)
- Sophie R D van der Schoor
- Department of Pediatrics, Division of Neonatology, Erasmus MC-Sophia Children's Hospital, Erasmus University, Rotterdam, Netherlands
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26
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Abstract
Infant foods have a special place among food products mainly because of nutritional aspects and preparations methods. A great increase of baby foods incomes is predicted in near future. Formulation, handling, and storage of baby foods are important to keep nutritional quality and physicochemical properties of these foods. During storage some reactions and interactions occur which change physicochemical and nutritional properties of baby foods. Lactose crystallization, Maillard reaction, oxidation, and interactions between micronutrients and other components are the most important aspect of preparation and storage of baby foods. These reactions and interactions influence physical properties such as flowability of powder, solubility, and other functional properties. Controlling of storage conditions such as temperature and moisture content and oxygen quantity in headspace of product is required to keep product quality. In this paper the composition and interactions of baby foods between major components and their effect on nutritional quality of baby foods are explained.
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Affiliation(s)
- Ali Nasirpour
- Nancy-Université, ENSAIA-INPL, Laboratoire de Science et Génie Alimentaires, 2 av. de la Forêt de Haye, Vandoeuvre lés Nancy 54505, France.
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Rees WD, Hay SM, Antipatis C. The effect of dietary protein on the amino acid supply and threonine metabolism in the pregnant rat. ACTA ACUST UNITED AC 2006; 46:227-39. [PMID: 16733043 DOI: 10.1051/rnd:2006015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 02/24/2006] [Indexed: 11/14/2022]
Abstract
To characterise the effects of dietary protein content on threonine metabolism during pregnancy, rats were fed diets containing 18% or 9% protein and then killed at different stages of gestation. Serum threonine concentrations fell significantly faster in the animals fed the diet containing 9% protein when compared to those fed the diet containing 18% protein. On day 4 of gestation the rate of threonine oxidation was higher in maternal liver homogenates prepared from the animals fed the diet containing 18% protein. The rate of threonine oxidation by liver homogenates fell as gestation proceeded in both diet groups. The activity of threonine dehydrogenase in the maternal liver was unaffected by dietary protein content at all stages of gestation. Serine-threonine dehydratase activity in homogenates of the maternal liver was transiently increased during the early stages of gestation in the animals fed high protein diets but was unchanged in the low protein groups. There was an increase in serine-threonine dehydratase activity in the kidney during the later stages of gestation but this was unaffected by the protein content of the maternal diet. These data show that the changes in free threonine concentrations cannot be accounted for through changes in the oxidation rate and suggest that some other factor influences the unusual metabolism of this amino acid during gestation.
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Affiliation(s)
- William D Rees
- The Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen, AB21 9SB, Scotland.
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Abstract
Threonine kinetics, threonine oxidative pathway, and the relationship between threonine and whole body protein turnover were quantified in 10 healthy term infants during the first 48 h after birth. The kinetic data were obtained 6 h after the last feed (fasting) and in response to formula feeding, using [U-(13)C(4),(15)N]threonine, [(2)H(5)]phenylalanine, and [(15)N]glycine tracers. The rate of carbon dioxide production (Vco(2)) and (13)C enrichment of the expired CO(2) were measured to quantify the rate of oxidation of threonine. The rate of appearance (R(a)) of threonine (136 +/- 37 micromol.kg(-1).h(-1)) was higher in newborn infants than that reported in adults. Formula feeding resulted in a significant decrease in threonine R(a) (P < 0.05). A significant positive correlation was seen between phenylalanine R(a) and threonine R(a), both during fasting and after formula feeding (r(2) = 0.65). In contrast to a 1:1 ratio of threonine and phenylalanine in mixed muscle protein, threonine R(a) relative to phenylalanine R(a) was 2.2 +/- 0.4. The fractional rate of threonine flux oxidized was 20% during fasting and 26% (P < 0.05) in response to nutrient administration. There was a significant correlation between plasma threonine concentration and threonine oxidation (r(2) = 0.75). No measurable incorporation of threonine in plasma glycine was seen. These data suggest that threonine is exclusively degraded by the glycine-independent serine/threonine dehydratase pathway. A higher flux of threonine relative to phenylalanine indicates higher turnover of threonine enriched proteins.
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Affiliation(s)
- Prabhu S Parimi
- Schwartz Center for Metabolism & Nutrition, Bell Greve Bldg., Room G-735, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA.
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Maggio L, Zuppa AA, Sawatzki G, Valsasina R, Schubert W, Tortorolo G. Higher urinary excretion of essential amino acids in preterm infants fed protein hydrolysates. Acta Paediatr 2005; 94:75-84. [PMID: 15858965 DOI: 10.1111/j.1651-2227.2005.tb01792.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM Protein hydrolysates have been introduced in preterm formulae, but it is not clear whether they are needed for the feeding of preterm infants. We designed a randomized, controlled trial to test the effects of a preterm formula with hydrolysed cow's milk proteins on short-term growth and urinary and plasma amino acids levels. METHODS Infants with a birthweight < or = 1750 g and gestational age < or = 34 wk fed a conventional preterm infant formula (formula B) or a hydrolysed formula (formula A). Weight was measured daily; length, head circumference, mid-arm circumference and total skinfold thickness were measured weekly. Blood and urine were analysed for amino acid concentrations at start, 14 and 28 d. RESULTS Twenty-one infants met the criteria for randomization. The daily feeding volumes were: formula A 172.8 +/- 5.6 vs formula B 170.1 +/- 2.8 ml/kg/d. Infants fed with formula A showed slower weight gain (17.4 +/- 3.4 vs 20.5 +/- 3.3 g/kg/d; p = 0.045) and lower mean change in Z-scores for weight (-0.18 +/- 0.16 vs 0.00 +/- 0.09; p = 0.009) and for head circumference (-0.06 +/- 0.13 vs 0.06 +/- 0.13; p = 0.049). After 14 d, infants receiving formula A had statistically significant higher urinary levels of essential amino acids compared to infants receiving formula B. CONCLUSION Our results support the hypothesis of less nutritional value of hydrolysed versus conventional preterm formulae. Higher renal excretion of essential amino acids may be one of the mechanisms involved. These findings must be confirmed by further studies with larger sample sizes and protein hydrolysates with different degrees of hydrolysis.
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Affiliation(s)
- L Maggio
- Division of Neonatology, Department of Paediatrics, Catholic University of the Sacred Heart, Rome, Italy.
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Darling PB, Dunn M, Gilani GS, Ball RO, Pencharz PB. Phenylalanine kinetics differ between formula-fed and human milk-fed preterm infants. J Nutr 2004; 134:2540-5. [PMID: 15465744 DOI: 10.1093/jn/134.10.2540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Infants fed casein-dominant formulas have higher plasma phenylalanine and tyrosine concentrations than those fed mother's milk. Conversely, elevated plasma threonine concentrations are observed in infants fed whey-dominant formulas. We recently showed that formula-fed preterm infants have a lower capacity to degrade threonine than do preterm infants fed mother's milk. We hypothesized that these same infants (n = 18) would differ in their catabolism of phenylalanine in response to phenylalanine loads provided by formulas with increasing casein content of formulas (whey:casein 60:40, 40:60, and 20:80) compared with preterm infants fed mother's milk. Plasma phenylalanine concentrations significantly rose (49, 46, 79 micromol . L(-1) for whey:casein 60:40, 40:60, and 20:80, respectively, pooled SD 8, P < 0.05); and plasma phenylalanine concentrations in infants fed mother's milk were low (40 +/- 4 micromol . L(-1)). Using [1-(13)C]phenylalanine tracer and (13)CO(2) production in breath we found that although there was a significant positive relation between phenylalanine oxidation and phenylalanine intake in formula-fed infants (r(2) = 0.43, P = 0.03), these infants were not able to increase their oxidation of phenylalanine enough to prevent a significant rise in plasma phenylalanine when fed the 20:80 formula. Compared to infants fed mother's milk, formula-fed infants had significantly lower phenylalanine oxidation (39.1 vs. 30.7% of phenylalanine intake, respectively, P < 0.05). We conclude that one of the mechanisms for the differences in plasma amino acid concentration between formula-fed and mother's milk-fed preterm infants may be in vivo down-regulated catabolism of 2 important essential amino acids (phenylalanine in addition to threonine) in formula-fed preterm infants.
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Affiliation(s)
- Pauline B Darling
- Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
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Abstract
Few data exist on amino acid needs in infants and children, mainly because until recently, amino acid requirements were determined using nitrogen balance. The advent of the indicator amino acid oxidation (IAAO) method permits studies to be conducted with minimal adaptation to the test amino acid. In light of the very limited data available for human infants, toddlers, and children, it was proposed that a factorial approach should be used to estimate their essential amino acid requirements. Using amino acid oxidation techniques, dietary essential amino acid requirements in adults have been nearly completed. Data on changes in total body potassium are now available for infants and children. From these data it is possible to calculate protein deposition during growth, and hence, it is now possible to estimate the amino acid requirements in children using a factorial model. However, there has been no independent verification of the model. Recently we determined total branched chain-amino acid requirements for young adults and children, and we can provide data to support the validity of the factorial model. IAAO has been used on children with liver disease as young as 3 y. The minimally invasive IAAO model opens the door for determination of dietary essential amino acid requirements in infants and children during health and disease. For study of preterm neonates, we used a piglet model to show that the amino acid needs for parenteral feeding are markedly reduced for several essential amino acids; this suggests that current commercial total parenteral nutrition amino acid solutions are less than ideal.
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Affiliation(s)
- Paul B Pencharz
- Department of Paediatrics, University of Toronto, and Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8.
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Kelleher SL, Chatterton D, Nielsen K, Lönnerdal B. Glycomacropeptide and alpha-lactalbumin supplementation of infant formula affects growth and nutritional status in infant rhesus monkeys. Am J Clin Nutr 2003; 77:1261-8. [PMID: 12716681 DOI: 10.1093/ajcn/77.5.1261] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Advances in dairy technology make it possible to enrich infant formula with specific bovine milk components that may enhance nutrient status. Glycomacropeptide, a carbohydrate-rich casein peptide, may increase absorption of calcium, iron, or zinc. alpha-Lactalbumin, a major breast-milk protein, may contribute to a balanced amino acid pattern and increase calcium and zinc absorption. OBJECTIVE We determined the effects of glycomacropeptide- and alpha-lactalbumin-supplemented infant formula on growth; trace mineral status; iron, zinc, and calcium absorption; and plasma amino acid, blood urea nitrogen, and plasma insulin concentrations. DESIGN Infant rhesus monkeys (n = 5 infants per group) were breastfed or fed control or alpha-lactalbumin- or glycomacropeptide-supplemented formula from birth to 4 mo of age. Hematologic measures and growth were assessed monthly. Mineral absorption was measured with radioisotopes and whole body counting. RESULTS Infants fed glycomacropeptide had higher food intake than did other formula-fed infants. Infants fed glycomacropeptide or control formula had higher hematocrit values than did infants that were breastfed or fed alpha-lactalbumin. Infants fed glycomacropeptide or control formula had higher plasma zinc and zinc absorption than did breastfed infants. Where differences were observed, breastfed infants and infants fed alpha-lactalbumin had similar plasma essential amino acid and insulin profiles, which were different from those of infants fed glycomacropeptide or control formula. CONCLUSIONS Glycomacropeptide- or alpha-lactalbumin-supplemented formula has no adverse effects on nutritional status in infant monkeys. Glycomacropeptide supplementation increases zinc absorption, which may permit the reduction of formula zinc concentrations, and alpha-lactalbumin supplementation promotes a plasma amino acid pattern similar to that of breastfed infant monkeys.
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Affiliation(s)
- Shannon L Kelleher
- Department of Nutrition and California National Primate Research Center, University of California, Davis, CA 95616, USA
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Edgar AJ. The human L-threonine 3-dehydrogenase gene is an expressed pseudogene. BMC Genet 2002; 3:18. [PMID: 12361482 PMCID: PMC131051 DOI: 10.1186/1471-2156-3-18] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2002] [Accepted: 10/02/2002] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND L-threonine is an indispensable amino acid. One of the major L-threonine degradation pathways is the conversion of L-threonine via 2-amino-3-ketobutyrate to glycine. L-threonine dehydrogenase (EC 1.1.1.103) is the first enzyme in the pathway and catalyses the reaction: L-threonine + NAD+ = 2-amino-3-ketobutyrate + NADH. The murine and porcine L-threonine dehydrogenase genes (TDH) have been identified previously, but the human gene has not been identified. RESULTS The human TDH gene is located at 8p23-22 and has 8 exons spanning 10 kb that would have been expected to encode a 369 residue ORF. However, 2 cDNA TDH transcripts encode truncated proteins of 157 and 230 residues. These truncated proteins are the result of 3 mutations within the gene. There is a SNP, A to G, present in the genomic DNA sequence of some individuals which results in the loss of the acceptor splice site preceding exon 4. The acceptor splice site preceding exon 6 was lost in all 23 individuals genotyped and there is an in-frame stop codon in exon 6 (CGA to TGA) resulting in arginine-214 being replaced by a stop codon. These truncated proteins would be non-functional since they have lost part of the NAD+ binding motif and the COOH terminal domain that is thought to be involved in binding L-threonine. TDH mRNA was present in all tissues examined. CONCLUSIONS The human L-threonine 3-dehydrogenase gene is an expressed pseudogene having lost the splice acceptor site preceding exon 6 and codon arginine-214 (CGA) is mutated to a stop codon (TGA).
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Affiliation(s)
- Alasdair J Edgar
- Tissue Engineering & Regenerative Medicine Centre, Division of Investigative Science, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Chelsea & Westminster Hospital, London, United Kingdom.
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Abstract
Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.
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Affiliation(s)
- Catherine J Klein
- Life Sciences Research Office, 9650 Rockville Pike, Bethesda, Maryland 20814, USA.
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35
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Abstract
The removal of the 1-carbon of threonine can occur via threonine dehydrogenase or threonine aldolase, this carbon ending up in glycine to be liberated by the mitochondrial glycine cleavage system and producing CO(2). Alternatively, in the threonine dehydratase pathway, the 1-carbon ends up in alpha-ketobutyrate, which is oxidized in the mitochondria to CO(2). Rat hepatocytes, incubated in Krebs-Henseleit medium, were incubated with 0.5 mM L-[1-(14)C]threonine, and (14)CO(2) production was measured. Added glycine (0.3 mM) marginally suppressed threonine oxidation. Cysteamine (0.5 mM), a potent inhibitor of the glycine cleavage system, reduced threonine oxidation to 65% of controls. However, alpha-cyanocinnamate (0.5 mM), a competitive inhibitor of mitochondrial alpha-keto acid uptake, reduced threonine oxidation to 35% of controls. These data provided strong evidence that approximately 65% of threonine oxidation occurs through the glycine-independent threonine dehydratase pathway. Glucagon (10(-7) M) increased threonine oxidation and stimulated threonine uptake by these cells. In summary, the majority of threonine oxidation occurs through the threonine dehydratase pathway in rat hepatocytes, and threonine oxidation is increased by glucagon, which also increases threonine's transport.
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Affiliation(s)
- J D House
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X9, Canada
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Szajewska H, Albrecht P, Stoitiska B, Prochowska A, Gawecka A, Laskowska-Klita T. Extensive and partial protein hydrolysate preterm formulas: the effect on growth rate, protein metabolism indices, and plasma amino acid concentrations. J Pediatr Gastroenterol Nutr 2001; 32:303-9. [PMID: 11345180 DOI: 10.1097/00005176-200103000-00013] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND The use of protein hydrolysate preterm formulas is restricted because data on their nutritional adequacy are scarce. The authors evaluated the rate of growth and indices of protein metabolism in low-birth weight infants fed extensive and partial protein hydrolysate preterm formula followed for 12 weeks. METHODS A total of 61 low-birth weight infants were assigned randomly to receive extensive protein hydrolysate preterm formula (EH: n = 16), partial protein hydrolysate preterm formula (PH: n = 15), and standard preterm formula (SF; n = 15), or were fed their own mother's fortified breast milk (FBM; n = 15). The infants were investigated at study entry, and at 4, 8, and 12 weeks after study entry. RESULTS There were no differences with respect to growth rate (weight gain, increments in length and head circumference), urea, albumin, prealbumin, transferrin, and plasma amino acid concentrations (except for tyrosine on a single occasion) according to the degree of hydrolysis. There were also no differences between groups fed hydrolyzed formulas and SF. However, several differences were found when EH and PH were compared with FBM. Weight gain from the entry to 12 weeks, serum urea at 12 weeks, and total plasma essential amino acids at 8 weeks were significantly higher in groups fed EH and PH than in those fed FBM. In addition, valine was significantly higher in groups fed PH (P < 0.05) than in the group fed FBM at 8 and 12 weeks, tyrosine was higher in EH and PH in comparison with FBM at 4 weeks, and in PH versus FBM at 12 weeks after study entry. CONCLUSIONS This study suggests that experimental EH and PH are at least nutritionally equivalent to SFs.
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Affiliation(s)
- H Szajewska
- Department of Paediatric Gastroenterology & Nutrition, The Medical University of Warsaw, Poland.
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Rigo J, Boehm G, Georgi G, Jelinek J, Nyambugabo K, Sawatzki G, Studzinski F. An infant formula free of glycomacropeptide prevents hyperthreoninemia in formula-fed preterm infants. J Pediatr Gastroenterol Nutr 2001; 32:127-30. [PMID: 11321379 DOI: 10.1097/00005176-200102000-00006] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND Hyperthreoninemia is a well-known phenomenon in infants fed a whey protein-predominant formula. Sweet whey is commonly used for the production of these whey-predominant infant milk formulas. Sweet whey contains not only whey proteins but also the threonine-rich glycomacropeptide (GMP). In the current study, an experimental formula based on acid whey without GMP and a formula based on sweet whey with GMP (threonine content 17.2% higher than in the experimental formula) but otherwise with identical composition were tested with particular respect to threonine metabolism. METHODS Fourteen preterm infants appropriate for gestational age were enrolled in this randomized cross-over study. After a feeding period of at least 7 days, the nutrition of each infant was switched to the other formula for the second feeding period. At the end of each feeding period, the concentrations of creatinine and amino acids in the plasma and in the urine were measured. RESULTS In the plasma, the threonine concentration was significantly lower in the group fed the experimental GMP-free formula than in the group fed the sweet whey formula (P < 0.001). Renal excretion of all essential amino acids was generally very low and less than 2% of the intake, indicating that the kidneys had no marked homeostatic function with respect to plasma amino acid. The plasma concentrations of the threonine metabolites glycine and serine, and that of urea were not influenced by diet. CONCLUSION Feeding a whey protein-predominant bovine milk produced from acid whey protein reduces significantly the hyperthreoninemia commonly found in formula-fed preterm infants. Thus, acid whey formulas should be recommended for feeding preterm infants.
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Affiliation(s)
- J Rigo
- Hospital de la Citadelle, Department of Neonatology, University of Liege, Belgium
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Brunton JA, Ball RO, Pencharz PB. Current total parenteral nutrition solutions for the neonate are inadequate. Curr Opin Clin Nutr Metab Care 2000; 3:299-304. [PMID: 10929677 DOI: 10.1097/00075197-200007000-00010] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The amino acid requirements of the parenterally fed neonate are poorly defined. Newborn infants are at risk for amino acid deficiency and toxicity, due to lack of small intestinal metabolism and metabolic immaturity. We discuss recent evidence that identifies inadequacies of commercial amino acid solutions with respect to the balance and quantity of aromatic amino acids, and sulphur amino acids. We present data demonstrating that impaired small intestinal metabolism (or lack of first pass metabolism) alters the whole body requirement for methionine, threonine, and arginine, and discuss the potential adverse effects of excess or inadequate parenteral amino acid intake.
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Affiliation(s)
- J A Brunton
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
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Darling PB, Grunow J, Rafii M, Brookes S, Ball RO, Pencharz PB. Threonine dehydrogenase is a minor degradative pathway of threonine catabolism in adult humans. Am J Physiol Endocrinol Metab 2000; 278:E877-84. [PMID: 10780944 DOI: 10.1152/ajpendo.2000.278.5.e877] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The threonine dehydrogenase (TDG) pathway is a significant route of threonine degradation, yielding glycine in experimental animals, but has not been accurately quantitated in humans. Therefore, the effect of a large excess of dietary threonine, given either as free amino acid (+Thr) or as a constituent of protein (+P-Thr), on threonine catabolism to CO(2) and to glycine was studied in six healthy adult males using a 4-h constant infusion of L-[1-(13)C]threonine and [(15)N]glycine. Gas chromatography-combustion isotope ratio mass spectrometry was used to determine [(13)C]glycine produced from labeled threonine. Threonine intakes were higher on +Thr and +P-Thr diets compared with control (126, 126, and 50 micromol x kg(-1) x h(-1), SD 8, P < 0.0001). Threonine oxidation to CO(2) increased threefold in subjects on +Thr and +P-Thr vs. control (49, 45, and 15 micromol x kg(-1) x h(-1), SD 6, P < 0.0001). Threonine conversion to glycine tended to be higher on +Thr and +P-Thr vs. control (3.5, 3.4, and 1.6 micromol x kg(-1) x h(-1), SD 1.3, P = 0.06). The TDG pathway accounted for only 7-11% of total threonine catabolism and therefore is a minor pathway in the human adult.
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Affiliation(s)
- P B Darling
- The Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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Wilson DC, Rafii M, Ball RO, Pencharz PB. Threonine requirement of young men determined by indicator amino acid oxidation with use of L-[1-(13)C]phenylalanine. Am J Clin Nutr 2000; 71:757-64. [PMID: 10702170 DOI: 10.1093/ajcn/71.3.757] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Threonine is an indispensable amino acid with a complex degradative pathway. Use of the indicator amino acid oxidation technique should provide an estimate of the threonine requirement that is not affected by its metabolic pathway. OBJECTIVE Our objective was to determine the requirement for threonine in men by using the indicator amino acid oxidation method and to provide statistical estimates of the population mean and 95% CIs of the threonine requirement. We hypothesized that the current World Health Organization estimate of the threonine requirement, 7 mg*kg(-)(1)*d(-)(1) (based on nitrogen balance studies), is too low. DESIGN Six healthy men each received 6 different threonine intakes while consuming an energy-sufficient diet with 1.0 g L-amino acid mixture*kg(-)(1)*d(-)(1). The effect of graded alterations in dietary threonine intake on phenylalanine flux and oxidation was studied by using L-[1-(13)C]phenylalanine as the indicator amino acid. RESULTS The results of two-phase linear regression crossover analysis showed that the mean threonine requirement, based on indicator oxidation, was 19.0 mg*kg(-)(1)*d(-)(1) with an upper safe intake of 26.2 mg*kg(-)(1)*d(-)(1). CONCLUSIONS This is the first application of the indicator amino acid oxidation technique in humans to study the requirement for an indispensable amino acid with a complex degradative pathway. We found that the upper safe intake for 95% of the population is almost 4-fold higher than the current World Health Organization estimate.
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Affiliation(s)
- D C Wilson
- Departments of Nutritional Sciences and Paediatrics, University of Toronto, Canada
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Darling PB, Bross R, Wykes LJ, Ball RO, Pencharz PB. Isotopic enrichment of amino acids in urine following oral infusions of L-[1-(13)C]phenylalanine and L-[1-(13)C]lysine in humans: confounding effect of D-[13C]amino acids. Metabolism 1999; 48:732-7. [PMID: 10381147 DOI: 10.1016/s0026-0495(99)90172-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Urine sampling of the free amino acid pool serves to reflect plasma enrichment and is used as a noninvasive means to determine isotope enrichment in studies of amino acid metabolism. We determined the effect of D-[13C]phenylalanine and D-[13C]lysine content of tracers on urinary amino acid enrichment following oral infusion of L-[13C]phenylalanine in 18 preterm infants and L-[1-(13)C]lysine in seven healthy adult females. Urinary [13C]phenylalanine enrichment was higher (P < .0001) for L-[13C]phenylalanine containing 0.4% D-[13C]phenylalanine (28.6 +/- 7.1) versus L-[1-(13)C]phenylalanine that contained undetectable D-[13C]phenylalanine (10.2 +/- 1.5). D-[13C]phenylalanine, measured by chiral column gas chromatography-mass spectrometry (GC-MS), accounted for 10% to 30% (20.5% +/- 7%) of total phenylalanine in the urine of infants who received 0.4% D-[13C]phenylalanine, and was absent from the urine of infants receiving tracer with undetectable [13C]phenylalanine. Urinary L-[13C]phenylalanine enrichment did not differ between tracer groups (9.8 +/- 1.5 and 9.8 +/- 2.5). In adult females, the use of L-[1-(13)C]lysine (1.6% D-lysine) resulted in a higher (P < .02) urine total L,D-[13C]lysine enrichment compared with plasma enrichment (40.8 +/- 4.1 v 11.1 +/- 0.7). This study demonstrates the significant presence of D-[13C]amino acids in urine that originate as contaminants from commercially manufactured tracers, as a result of renal tubular discrimination of D-amino acids. A tracer containing detectable amounts of D-[13C]isomer cannot be recommended for any study in which urine will be used to reflect enrichment in the arterial plasma pool.
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Affiliation(s)
- P B Darling
- Research Institute, The Hospital for Sick Children, and Department of Nutritional Sciences, University of Toronto, Ontario, Canada
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