scholarly journals Large neutral amino acids block phenylalanine transport into brain tissue in patients with phenylketonuria

1999 ◽  
Vol 103 (8) ◽  
pp. 1169-1178 ◽  
Author(s):  
Joachim Pietz ◽  
Roland Kreis ◽  
André Rupp ◽  
Ertan Mayatepek ◽  
Dietz Rating ◽  
...  
Keyword(s):  
Amino Acids ◽  
Brain Tissue ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Phenylalanine Transport

scholarly journals Distribution Volume of Radiolabeled Large Neutral Amino Acids in Brain Tissue

1998 ◽  
Vol 18 (12) ◽  
pp. 1288-1293 ◽  
Author(s):  
Sung-Cheng Huang ◽  
David B. Stout ◽  
Randa E. Yee ◽  
Nagichettiar Satyamurthy ◽  
Jorge R. Barrio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brain Tissue ◽  
Blood Brain Barrier ◽  
Distribution Volume ◽  
Neutral Amino Acid ◽  
Large Neutral Amino Acid ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Amino Acid Levels

Variations in the cerebellum to plasma ratio at late times in 6-[18F]fluoro-l-DOPA studies are shown to be consistent with competitive binding of large neutral amino acids for a common transporter in the blood—brain barrier and the stability of brain tissue large neutral amino acid level in the presence of plasma level changes. The distribution volume of an inert large neutral amino acid can be estimated from plasma and tissue large neutral amino acid levels and apparent half-saturation concentrations ( Km) of the transporter in the blood—brain barrier. Stability of brain large neutral amino acid levels is supported by literature findings and can be explained by high saturation of the large neutral amino acid transporter at physiologic conditions.

Atypical amino acids inhibit histidine, valine, or lysine transport into rat brain

1983 ◽  
Vol 245 (4) ◽  
pp. R556-R563 ◽  
Author(s):  
J. K. Tews ◽  
A. E. Harper
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
Brain Slices ◽  
Aromatic Amino Acids ◽  
Brain Barrier ◽  
Basic Amino Acids ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Single Meal

Transport of histidine, valine, or lysine into rat brain slices and across the blood-brain barrier (BBB) was determined in the presence of atypical nonprotein amino acids. Competitors of histidine and valine transport in slices were large neutral amino acids including norleucine, norvaline, alpha-aminooctanoate, beta-methylphenylalanine, and alpha-aminophenylacetate. Less effective were aromatic amino acids with ring substituents; ineffective were basic amino acids and omega-amino isomers of norleucine and aminooctanoate. Lysine transport was moderately depressed by homoarginine or ornithine plus arginine; large neutral amino acids were also similarly inhibitory. Histidine or valine transport across the BBB was also strongly inhibited by large neutral amino acids that were the most effective competitors in the slices (norvaline, norleucine, alpha-aminooctanoate, and alpha-aminophenylacetate); homoarginine and 8-aminooctanoate were ineffective. Homoarginine, ornithine, and arginine almost completely blocked lysine transport, but the large neutral amino acids were barely inhibitory. When rats were fed a single meal containing individual atypical large neutral amino acids or homoarginine, brain pools of certain large neutral amino acids or of arginine and lysine, respectively, were depleted.

scholarly journals Large Neutral Amino Acids (LNAAs) Supplementation Improves Neuropsychological Performances in Adult Patients with Phenylketonuria

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1092 ◽  
Author(s):  
Iris Scala ◽  
Maria Pia Riccio ◽  
Maria Marino ◽  
Carmela Bravaccio ◽  
Giancarlo Parenti ◽  
...  
Keyword(s):  
Amino Acids ◽  
Executive Functions ◽  
Metabolic Control ◽  
Cognitive Functions ◽  
Well Being ◽  
Wisconsin Card Sorting Test ◽  
Card Sorting ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Poor Metabolic Control

Phenylketonuria is an inborn error of phenylalanine (Phe) metabolism diagnosed by newborn screening and treated early with diet. Although diet prevents intellectual disability, patients often show impairment of executive functions, working memory, sustained attention, and cognitive flexibility. Large neutral amino acids (LNAAs) have been proposed as a dietary supplement for PKU adults. Few studies show that LNAAs may help in improving metabolic control as well as cognitive functions. In this study, 10 adult PKU patients with poor metabolic control were treated for 12 months with LNAAs (MovisCom, 0.8–1 g/kg/day) and underwent Phe and Tyrosine (Tyr) monitoring monthly. Neuropsychological assessment was performed at T0, T+3, and T+12 months by using the American Psychological General Well-Being Index, the Wisconsin Card Sorting Test, the Test of Attentional Performance, and the 9-Hole Peg Test. No change in plasma Phe levels was observed during LNAAs supplementation, while Tyr levels significantly improved during LNAAs supplementation (p = 0.03). Psychometric tests showed an improvement of distress and well-being rates, of executive functions, attention, and vigilance, whereas no difference was noted regarding hand dexterity. This study adds evidence of the advantage of LNAAs supplementation in improving cognitive functions and well-being in patients with PKU with poor metabolic control.

scholarly journals Trans-placental Gradients of Large Neutral Amino Acids (LNAA) in Baboon Pregnancy With Fasting,Feeding and Tryptophan (TRP) Infusion † 298

1998 ◽  
Vol 43 ◽  
pp. 53-53
Author(s):  
S Rastogi ◽  
K Abildskov ◽  
S S Daniel ◽  
M Garland ◽  
K Schulze ◽  
...  
Keyword(s):  
Amino Acids ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids

Acute effects of aspartame on large neutral amino acids and monoamines in rat brain

Life Sciences ◽  
1983 ◽  
Vol 32 (14) ◽  
pp. 1651-1658 ◽  
Author(s):  
John D. Fernstrom ◽  
Madelyn H. Fernstrom ◽  
Marcia A. Gillis
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Acute Effects ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids

Large neutral amino acids in the treatment of phenylketonuria (PKU)

2006 ◽  
Vol 29 (6) ◽  
pp. 732-738 ◽  
Author(s):  
R. Matalon ◽  
K. Michals-Matalon ◽  
G. Bhatia ◽  
E. Grechanina ◽  
P. Novikov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids

scholarly journals Beneficial Effects of Slow-Release Large Neutral Amino Acids after a Phenylalanine Oral Load in Patients with Phenylketonuria

Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 4012
Author(s):  
Iris Scala ◽  
Daniela Concolino ◽  
Anna Nastasi ◽  
Giulia Esposito ◽  
Daniela Crisci ◽  
...  
Keyword(s):  
Amino Acids ◽  
Slow Release ◽  
Good Adherence ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Beneficial Effects ◽  
Adherence To Diet ◽  
Low Protein ◽  
Single Oral Administration ◽  
Stable Plasma

The mainstay of phenylketonuria treatment is a low protein diet, supplemented with phenylalanine (Phe)-free protein substitutes and micronutrients. Adhering to this diet is challenging, and even patients with good metabolic control who follow the dietary prescriptions in everyday life ignore the recommendations occasionally. The present study explores the ability of slow-release large neutral amino acids (srLNAAs) to prevent Phe increase following a Phe dietary load. Fourteen phenylketonuric patients aged ≥13 years were enrolled in a 6-week protocol. Oral acute Phe loads of 250 and 500 mg were added to the evening meal together with srLNAAs (0.5 gr/kg). Phe and tyrosine were dosed before dinner, 2h-after dinner, and after the overnight fast. After oral Phe loads, mean plasma Phe remained stable and below 600 µmol/L. No Phe peaks were registered. Tyrosine levels significantly increased, and Phe/Tyrosine ratio decreased. No adverse events were registered. In conclusion, a single oral administration of srLNAAs at the dose of 0.5 gr/kg is effective in maintaining stable plasma Phe during acute oral loads with Phe-containing food and may be added to the dietetic scheme in situations in which patients with generally good adherence to diet foresee a higher than prescribed Phe intake due to their commitments.

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