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Role of amino acid supplementation in the prevention of necrotizing enterocolitis in preterm neonates - a review of current evidences.
Garg, BD, Kabra, NS
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2018;(17):2349-2366
Abstract
BACKGROUND Necrotizing enterocolitis (NEC) is one of the most common acute and fatal gastrointestinal emergency in very low birth weight (VLBW) preterm neonates with mortality range from 15 to 30%. NEC is likely due to multifactorial process such as oxidative injury, ischemic necrosis, and over-reactive inflammatory response to intestinal microbes. AIMS To evaluate the role of amino acid supplementation for reduction of neonatal NEC in preterm neonates. METHOD The literature search was done for various randomized control trial (RCT) by searching the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, Web of Science, Scopus, Index Copernicus, African Index Medicus (AIM), Thomson Reuters (ESCI), Chemical Abstracts Service (CAS) and other database. RESULTS This review included 15 RCTs that fulfilled inclusion criteria. The total neonates enrolled in these different RCT are 3424 (amino acid group 1711 and control 1713). Almost all participating neonates were of VLBW or extremely low birth weight (ELBW). In two trials, birth weight was between 1500-2000 grams. The intervention was started within first few days after birth and continued up to 30th day of postnatal age in most of the trials. In two trials, intervention was continued up to 120th day of postnatal age. Arginine, glutamine and N-acetyl cysteine (NAC) were used at the dose of 1.5 mol/kg/day (261 mg/kg/day), 0.3 grams/kg/day and 16-32 mg/kg/day, respectively. CONCLUSION Role of amino acid in the prevention of neonatal NEC is not exclusively supported by the current evidence. Only three studies were able to show reduction in the incidence of NEC with amino acid supplementation (arginine, glutamine), and the remaining studies did not report any positive effect. Amino acid supplementation was not associated with significant reduction in mortality due to any causes. However, arginine supplementation was associated with significant reduction in mortality due to NEC. Two studies on glutamine were reported significant reduction in the incidence of invasive infection. Only one study reported significant positive effects on growth parameters and less time to reach full enteral feeds. None of the studies showed any effect on the duration of hospital stay.
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The metabolic roles of free amino acids during seed development.
Amir, R, Galili, G, Cohen, H
Plant science : an international journal of experimental plant biology. 2018;:11-18
Abstract
Amino acids play vital roles in the central metabolism of seeds. They are primarily utilized for the synthesis of seed-storage proteins, but also serve as precursors for the biosynthesis of secondary metabolites and as a source of energy. Here, we aimed at describing the knowledge accumulated in recent years describing the changes occurring in the contents of free amino acids (FAAs) during seed development. Since several essential amino acids are found in low levels in seeds (e.g., Lys, Met, Thr, Val, Leu, Ile and His), or play unique functional roles in seed development (e.g., Pro and the non-proteinogenic γ-aminobutyrate [GABA]), we also briefly describe studies carried out in order to alter their levels in seeds and determine the effects of the manipulation on seed biology. The lion share of these studies highlights strong positive correlations between the biosynthetic pathways of FAAs, meaning that when the levels of a certain amino acid change in seeds, the contents of other FAAs tend to elevate as well. These observations infer a tight regulatory network operating in the biosynthesis of FAAs during seed development.
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Dose-Dependent Effects of Randomized Intraduodenal Whey-Protein Loads on Glucose, Gut Hormone, and Amino Acid Concentrations in Healthy Older and Younger Men.
Giezenaar, C, Luscombe-Marsh, ND, Hutchison, AT, Standfield, S, Feinle-Bisset, C, Horowitz, M, Chapman, I, Soenen, S
Nutrients. 2018;(1)
Abstract
Protein-rich supplements are used widely for the prevention and management of malnutrition in older people. We have reported that healthy older, compared to younger, adults have less suppression of energy intake by whey-protein-effects on appetite-related hormones are unknown. The objective was to determine the effects of intraduodenally administered whey-protein on glucose, gut hormone, and amino acid concentrations, and their relation to subsequent ad libitum energy intake at a buffet meal, in healthy older and younger men. Hydrolyzed whey-protein (30 kcal, 90 kcal, and 180 kcal) and a saline control (~0 kcal) were infused intraduodenally for 60 min in 10 younger (19-29 years, 73 ± 2 kg, 22 ± 1 kg/m²) and 10 older (68-81 years, 79 ± 2 kg, 26 ± 1 kg/m²) healthy men in a randomized, double-blind fashion. Plasma insulin, glucagon, gastric inhibitory peptide (GIP), glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), and amino acid concentrations, but not blood glucose, increased, while ghrelin decreased during the whey-protein infusions. Plasma GIP concentrations were greater in older than younger men. Energy intake correlated positively with plasma ghrelin and negatively with insulin, glucagon, GIP, GLP-1, PYY, and amino acids concentrations (p < 0.05). In conclusion, intraduodenal whey-protein infusions resulted in increased GIP and comparable ghrelin, insulin, glucagon, GIP, GLP-1, PYY, and amino acid responses in healthy older and younger men, which correlated to subsequent energy intake.
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The role of amino-acid PET in the light of the new WHO classification 2016 for brain tumors.
Suchorska, B, Albert, NL, Bauer, EK, Tonn, JC, Galldiks, N
The quarterly journal of nuclear medicine and molecular imaging : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of.... 2018;(3):267-271
Abstract
Since its introduction in 2016, the revision of the World Health Organization (WHO) classification of central nervous system tumors has already changed the diagnostic and therapeutic approach in glial tumors. Blurring the lines between entities formerly labelled as "high-grade" or "low-grade", molecular markers define distinct biological subtypes with different clinical course. This new classification raises the demand for non-invasive imaging methods focusing on depicting metabolic processes. We performed a review of current literature on the use of amino-acid PET (AA-PET) for obtaining diagnostic or prognostic information on glioma in the setting of the current WHO 2016 classification. So far, only a few studies have focused on combining molecular genetic information and metabolic imaging using AA-PET. The current review summarizes the information available on "molecular grading" as well as prognostic information obtained from AA-PET and delivers an insight into a possible interrelation between metabolic imaging and glioma genetics. Within the framework of molecular characterization of gliomas, metabolic imaging using AA-PET is a promising tool for non-invasive characterization of molecular features and to provide additional prognostic information. Further studies incorporating molecular and metabolic features are necessary to improve the explanatory power of AA-PET in glial tumors.
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Redesign of LAOBP to bind novel l-amino acid ligands.
Banda-Vázquez, J, Shanmugaratnam, S, Rodríguez-Sotres, R, Torres-Larios, A, Höcker, B, Sosa-Peinado, A
Protein science : a publication of the Protein Society. 2018;(5):957-968
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Abstract
Computational protein design is still a challenge for advancing structure-function relationships. While recent advances in this field are promising, more information for genuine predictions is needed. Here, we discuss different approaches applied to install novel glutamine (Gln) binding into the Lysine/Arginine/Ornithine binding protein (LAOBP) from Salmonella typhimurium. We studied the ligand binding behavior of two mutants: a binding pocket grafting design based on a structural superposition of LAOBP to the Gln binding protein QBP from Escherichia coli and a design based on statistical coupled positions. The latter showed the ability to bind Gln even though the protein was not very stable. Comparison of both approaches highlighted a nonconservative shared point mutation between LAOBP_graft and LAOBP_sca. This context dependent L117K mutation in LAOBP turned out to be sufficient for introducing Gln binding, as confirmed by different experimental techniques. Moreover, the crystal structure of LAOBP_L117K in complex with its ligand is reported.
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Metabolite normalization with local radiotherapy following breast tumor resection.
Arenas, M, Rodríguez, E, García-Heredia, A, Fernández-Arroyo, S, Sabater, S, Robaina, R, Gascón, M, Rodríguez-Pla, M, Cabré, N, Luciano-Mateo, F, et al
PloS one. 2018;(11):e0207474
Abstract
The aims of this study were to investigate changes in energy balance-associated metabolites associated with radiotherapy in patients with breast cancer, and to relate these changes to the clinical and pathological response-to-treatment. We studied 151 women with breast cancer who received radiotherapy following surgical excision of the tumor. Blood was obtained before and after the irradiation procedure. The control group was composed of 44 healthy women with a similar age distribution to that of the patients. We analyzed the concentrations of metabolites involved in glycolysis, citric acid cycle and amino acid metabolism using targeted quantitative metabolomics. Post-surgery, pre-radiotherapy, patients had major alterations in the serum concentrations of products of glycolysis, citric acid cycle and amino acid metabolism. The strongest alterations were decreases in serine, leucine and isoleucine concentrations. Alterations in metabolite levels were partially, or totally, reversed after irradiation; the concentrations of serine, leucine and isoleucine approached equivalence to those of the control group. Estrogen receptor-positive patients were those with lower concentrations, while triple negative patients had higher concentrations of these amino acids. The normalization of the amino acids serine, leucine and isoleucine concentrations could be clinically relevant because the normalization of these energy-balance metabolites would suggest that residual micro-metastatic disease had been effectively diminished by the radiotherapy, and may be an indicator of its efficacy.
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Saccharomyces cerevisiae adapted to grow in the presence of low-dose rapamycin exhibit altered amino acid metabolism.
Dikicioglu, D, Dereli Eke, E, Eraslan, S, Oliver, SG, Kirdar, B
Cell communication and signaling : CCS. 2018;(1):85
Abstract
BACKGROUND Rapamycin is a potent inhibitor of the highly conserved TOR kinase, the nutrient-sensitive controller of growth and aging. It has been utilised as a chemotherapeutic agent due to its anti-proliferative properties and as an immunosuppressive drug, and is also known to extend lifespan in a range of eukaryotes from yeast to mammals. However, the mechanisms through which eukaryotic cells adapt to sustained exposure to rapamycin have not yet been thoroughly investigated. METHODS Here, S. cerevisiae response to long-term rapamycin exposure was investigated by identifying the physiological, transcriptomic and metabolic differences observed for yeast populations inoculated into low-dose rapamycin-containing environment. The effect of oxygen availability and acidity of extracellular environment on this response was further deliberated by controlling or monitoring the dissolved oxygen level and pH of the culture. RESULTS Yeast populations grown in the presence of rapamycin reached higher cell densities complemented by an increase in their chronological lifespan, and these physiological adaptations were associated with a rewiring of the amino acid metabolism, particularly that of arginine. The ability to synthesise amino acids emerges as the key factor leading to the major mechanistic differences between mammalian and microbial TOR signalling pathways in relation to nutrient recognition. CONCLUSION Oxygen levels and extracellular acidity of the culture were observed to conjointly affect yeast populations, virtually acting as coupled physiological effectors; cells were best adapted when maximal oxygenation of the culture was maintained in slightly acidic pH, any deviation necessitated more extensive readjustment to additional stress factors.
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Ingestion of Insect Protein Isolate Enhances Blood Amino Acid Concentrations Similar to Soy Protein in A Human Trial.
Vangsoe, MT, Thogersen, R, Bertram, HC, Heckmann, LL, Hansen, M
Nutrients. 2018;(10)
Abstract
BACKGROUND Increased amino acid availability stimulates muscle protein synthesis (MPS), which is critical for maintaining or increasing muscle mass when combined with training. Previous research suggests that whey protein is superior to soy protein in regard to stimulating MPS and muscle mass. Nevertheless, with respect to a future lack of dietary protein and an increasing need for using eco-friendly protein sources it is of great interest to investigate the quality of alternative protein sources, like insect protein. OBJECTIVE Our aim was to compare the postprandial amino acid (AA) availability and AA profile in the blood after ingestion of protein isolate from the lesser mealworm, whey isolate, and soy isolate. DESIGN Six healthy young men participated in a randomized cross-over study and received three different protein supplementations (25 g of crude protein from whey, soy, insect or placebo (water)) on four separate days. Blood samples were collected at pre, 0 min, 20 min, 40 min, 60 min, 90 min, and 120 min. Physical activity and dietary intake were standardized before each trial, and participants were instructed to be fasting from the night before. AA concentrations in blood samples were determined using ¹H NMR spectroscopy. RESULTS A significant rise in blood concentration of essential amino acids (EAA), branched-chain amino acids (BCAA) and leucine was detected over the 120 min period for all protein supplements. Nevertheless, the change in AA profile was significantly greater after ingestion of whey than soy and insect protein (p < 0.05). Area under the curve (AUC) analysis and AA profile revealed comparable AA concentrations for soy and insect protein, whereas whey promoted a ~97% and ~140% greater AUC value than soy and insect protein, respectively. A tendency towards higher AA concentrations beyond the 120 min period was observed for insect protein. CONCLUSION We report that ingestion of whey, soy, and insect protein isolate increases blood concentrations of EAA, BCAA, and leucine over a 120 min period (whey > insect = soy). Insect protein induced blood AA concentrations similar to soy protein. However, a tendency towards higher blood AA concentrations at the end of the 120 min period post ingestion was observed for insect protein, which indicates that it can be considered a "slow" digestible protein source.
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The Association of Acylcarnitines and Amino Acids With Age in Dutch and South-Asian Surinamese Living in Amsterdam.
Muilwijk, M, Vaz, FM, Celis-Morales, C, Peters, RJG, van Valkengoed, IGM
The Journal of clinical endocrinology and metabolism. 2018;(10):3783-3791
Abstract
CONTEXT Type 2 diabetes and cardiovascular disease occur more frequently and at a younger age in South-Asians than Europeans. This may be related to differences in regulation of the fatty acid metabolism during aging. We compared age-related acylcarnitine and amino acid concentrations in Dutch and South-Asian Surinamese study participants. METHODS We measured types of acylcarnitine and amino acid concentrations in plasma (by tandem mass spectrometry) in a random subsample of 350 Dutch and 350 South-Asian Surinamese origin participants of the Healthy Life in an Urban Setting study (Amsterdam, Netherlands). We derived principal components (PCs) from the metabolites. Linear regression was used to assess differences in PCs and individual metabolite concentrations, and their age trends between the groups by sex. We adjusted for body mass index and intake of fat and total energy. RESULTS Mean age was 44.8 (SD, 13.3) years. Amino acid concentrations were higher among South-Asian Surinamese women compared with Dutch women; acylcarnitine and amino acid levels were higher among South-Asian Surinamese men than Dutch men. Metabolite levels increased similarly with age in both ethnic groups. Results remained similar after adjustment. CONCLUSION Ethnic differences in metabolite concentrations suggest that fatty acid and amino acid metabolism are more dysregulated among South-Asian Surinamese compared with Dutch from a young age. During adulthood, metabolites increase similarly in both ethnic groups.
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Update on amino acid transporter functions and on possible amino acid sensing mechanisms in plants.
Dinkeloo, K, Boyd, S, Pilot, G
Seminars in cell & developmental biology. 2018;:105-113
Abstract
Amino acids are essential components of plant metabolism, not only as constituents of proteins, but also as precursors of important secondary metabolites and as carriers of organic nitrogen between the organs of the plant. Transport across intracellular membranes and translocation of amino acids within the plant is mediated by membrane amino acid transporters. The past few years have seen the identification of a new family of amino acid transporters in Arabidopsis, the characterization of intracellular amino acid transporters, and the discovery of new roles for already known proteins. While amino acid metabolism needs to be tightly coordinated with amino acid transport activity and carbohydrate metabolism, no gene involved in amino acid sensing in plants has been unequivocally identified to date. This review aims at summarizing the recent data accumulated on the identity and function of amino acid transporters in plants, and discussing the possible identity of amino acid sensors based on data from other organisms.