scholarly journals Plasma Albumin Redox State Is Responsive to the Amino Acid Balance of Dietary Proteins in Rats Fed a Low Protein Diet

2019 ◽  
Vol 6 ◽  
Author(s):  
Yasuaki Wada ◽  
Xijier ◽  
Namiko Seto ◽  
Yosuke Komatsu ◽  
Muneya Tsuda ◽  
...  
Keyword(s):  
Amino Acid ◽  
Redox State ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Dietary Proteins ◽  
Plasma Albumin ◽  
Low Protein ◽  
Amino Acid Balance

scholarly journals Reasons why hypoalbuminaemia may or may not appear in protein-energy malnutrition

1977 ◽  
Vol 38 (1) ◽  
pp. 115-126 ◽  
Author(s):  
W. A. Coward ◽  
R. G. Whitehead ◽  
P. G. Lunn
Keyword(s):  
Amino Acid ◽  
Dietary Restriction ◽  
Protein Energy Malnutrition ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Albumin Concentration ◽  
Plasma Albumin ◽  
Low Protein ◽  
Protein Energy ◽  
Plasma Albumin Concentration

1.Investigations have been carried out in experimentally-malnourished rats in an attempt to explain the reasons for the development of the two main forms of protein-energy malnutrition in children, kwashiorkor and marasmus.2.Isoenergetic diets with values for protein: energy (P:E) of 0.21 (control diet; C) 0.032 (low-protein diet; LP) and 0.005 (very-low-protein diet; VLP) were fed to groups of twenty-six rats either ad lib. or in restricted amounts from 5 weeks of age. Rats were killed at the start of the experiment and 1, 2 and 3 or 4 weeks later. Estimations were made of plasma albumin, insulin, corticosterone and amino acid concentrations and of the total protein content of the gastrocnemius muscles and liver.3.Rats given diet LP ad lib. gained weight slowly and by week 1 plasma albumin concentration was slightly reduced. Rats given diet VLP ad lib. gradually lost weight and plasma albumin concentrations decreased continuously.4.In contrast the major effect of dietary restriction during the first 2 weeks of the experiment was to maintain plasma albumin concentrations at normal values, irrespective of the diet given.5.At later stages, however, when the ‘restricted’ animals had become very severely wasted, albumin concentrations decreased rapidly to values approaching those found in rats given diet VLP ad lib.6.When diets LP and VLP were given ad lib. body protein was proportionally distributed in favour of muscle rather than liver. For ‘restricted’ rats the reverse was true, at least up to the time when plasma albumin concentration began to decrease.7.Plasma corticosterone concentrations increased and insulin concentrations decreased when diets LP and VLP were fed in both an ad lib. and a ‘restricted’ regimen but the effects were significantly greater in the latter situation.8.Ad lib. feeding of diets LP and VLP produced a distorted plasma amino acid pattern resembling that of kwashiorkor, but although dietary restriction resulted in a decrease in total amino acid concentration, the plasma concentration ratio, non-essential amino acids:essential amino acids was virtually unaffected.9.It was concluded that whilst the lower the protein concentration in the diet the greater is the extent of hypoalbuminaemia which develops, dietary restriction with an increase in plasma glucocorticoid concentration and body-wasting can initially delay the development of the hypoalbuminaemia. However, in the final stages of wasting which ensue, low plasma albumin concentrations can appear because of a failure of the mechanisms which had earlier been able to preserve them at normal levels. It is possible that these two separate and distinct routes to hypoalbuminaemia observed in this study may have parallels in human situations in developing countries.

scholarly journals Plasma albumin redox state is superior to conventional biomarkers to indicate the presence of potential protein undernutrition

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Yasuaki Wada ◽  
Hirohisa Izumi ◽  
Takashi Shimizu ◽  
Yasuhiro Takeda
Keyword(s):  
Dietary Protein ◽  
Redox State ◽  
Hdl Cholesterol ◽  
Experimental Period ◽  
Diet Group ◽  
Protein Diet ◽  
Paraoxonase 1 ◽  
Low Protein Diet ◽  
Plasma Albumin ◽  
Low Protein

AbstractThe redox state of plasma albumin would reflect albumin synthesis rate, and could be useful to demonstrate the presence of potential protein undernutrition. Aiming to delineate the characteristics of plasma albumin redox state as a nutritional biomarker, adult male Wistar rats were maintained on AIN-93M (14% casein, control diet) or an AIN-93M-based low protein diet (5% casein) ad libitum for 4 weeks, and the two groups were compared by examining plasma albumin redox state, plasma/serum levels of conventional biomarkers for protein nutritional status, and plasma proteome. While no significant difference was seen in body weight at the end of the experimental period, plantaris muscle mass trended lower in the low protein diet group, implicating the manifestation of moderate protein undernutrition. The redox of plasma albumin was shifted to more oxidized state in the low protein diet group, and the shift persisted during the entire experimental period. In contrast, the levels of conventional biomarkers, plasma albumin and prealbumin, were initially decreased in the low protein diet group, and the differences were then dissolved later in the experimental period. Similarly, the levels of other biomarkers, plasma transferrin and serum retinol-binding protein-4, did not differ significantly at the end of the experimental period. Plasma proteomic analysis revealed that the abundances of proteins that constitute high-density lipoprotein (HDL), apolipoprotein A-II and paraoxonase-1, were decreased in the low protein diet group, which were then validated by confirming decreases in plasma HDL level, plasma HDL-cholesterol level, and serum paraoxonase-1 activity in the low protein diet group. According to epidemiological reports, dietary protein intake is positively associated with plasma HDL-cholesterol level, and the risk factors of cardiovascular diseases, including lower HDL-cholesterol level, are closely related to frailty. Thus, it can be conceived that moderate dietary protein insufficiency would increase cardiovascular risks, such as reduction in HDL level and function (paraoxonase-1 activity), which could prime the onset of amyotropic diseases later in life, such as sarcopenia and frailty. Collectively, moderate dietary protein insufficiency would lead to decreased skeletal muscle mass, and also attenuate circulating HDL level and function, which could even aggravate the attenuation of skeletal muscle accretion; the redox state of plasma albumin would be instrumental over conventional biomarkers as an indicator of potentially protein undernourished status.

scholarly journals The relative effects of a low-protein-high-carbohydrate diet on the free amino acid composition of liver and muscle

1976 ◽  
Vol 36 (2) ◽  
pp. 219-230
Author(s):  
P. G. Lunn ◽  
R. G. Whitehead ◽  
B. A. Baker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Acid Concentration ◽  
Free Amino ◽  
Essential Amino Acids ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Total Amino Acid ◽  
Low Protein

1. Free amino acid concentrations in the plasma have been compared with those in liver and quadriceps muscle, in rats fed on diets containing 209 (control) and 31 (low-protein) g protein/kg. The effects of the low-protein diet on diurnal variations in these values were also measured.2. In the plasma, the total amino acid concentration was significantly lower in animals given the low-protein diet, at all times of day except 12.00 hours. In the liver, and to a lesser extent the muscle, total amino acid concentration was maintained.3. In the control animals, diurnal variation in the concentrations of both essential and non-essential amino acids was very similar in plasma, liver and muscle. In animals given the low-protein diet, although the same diurnal pattern was maintained for non-essential amino acids, that occurring among the essential amino acids had virtually disappeared.4. In plasma, the mean 24 h concentration of essential amino acids decreased from 24· mmol/l in control animals to only 1·29 mmol/l in the low-protein-fed animals. Concentrations in muscle and liver were reduced by a similar proportion (from 8·6 to 5·56 μmol/g and from 8·67 to 5·05 μmol/g respectively). Conversely the concentrations of non-essential amino acids in animals given the low-protein diet were increased in plasma (from 1·53 to 2·00 mmol/l), muscle (from 12·5 to 14·3 μmol/g), and liver (from 16·8 to 20·5 μmol/g), muscle showing the lowest increase.5. With the exceptions of lysine, threonine, cystine and tyrosine, the concentrations of all other essential amino acids were reduced more in liver than in muscle. The relationship between this and the failure to maintain plasma albumin concentrations is discussed.

scholarly journals Serum metabolites associated with dietary protein intake: results from the Modification of Diet in Renal Disease (MDRD) randomized clinical trial

2019 ◽  
Vol 109 (3) ◽  
pp. 517-525 ◽  
Author(s):  
Casey M Rebholz ◽  
Zihe Zheng ◽  
Morgan E Grams ◽  
Lawrence J Appel ◽  
Mark J Sarnak ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Amino Acid ◽  
Dietary Protein ◽  
Protein Intake ◽  
Filtration Rate ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Dietary Protein Intake ◽  
Low Protein ◽  
P 16

ABSTRACT Background Accurate assessment of dietary intake is essential, but self-report of dietary intake is prone to measurement error and bias. Discovering metabolic consequences of diets with lower compared with higher protein intake could elucidate new, objective biomarkers of protein intake. Objectives The goal of this study was to identify serum metabolites associated with dietary protein intake. Methods Metabolites were measured with the use of untargeted, reverse-phase ultra-performance liquid chromatography–tandem mass spectrometry quantification in serum specimens collected at the 12-mo follow-up visit in the Modification of Diet in Renal Disease (MDRD) Study from 482 participants in study A (glomerular filtration rate: 25–55 mL · min−1 · 1.73 m−2) and 192 participants in study B (glomerular filtration rate: 13–24 mL · min−1 · 1.73 m−2). We used multivariable linear regression to test for differences in log-transformed metabolites (outcome) according to randomly assigned dietary protein intervention groups (exposure). Statistical significance was assessed at the Bonferroni-corrected threshold: 0.05/1193 = 4.2 × 10−5. Results In study A, 130 metabolites (83 known from 28 distinct pathways, including 7 amino acid pathways; 47 unknown) were significantly different between participants randomly assigned to the low-protein diet compared with the moderate-protein diet. In study B, 32 metabolites (22 known from 8 distinct pathways, including 4 amino acid pathways; 10 unknown) were significantly different between participants randomly assigned to the very-low-protein diet compared with the low-protein diet. A total of 11 known metabolites were significantly associated with protein intake in the same direction in both studies A and B: 3-methylhistidine, N-acetyl-3-methylhistidine, xanthurenate, isovalerylcarnitine, creatine, kynurenate, 1-(1-enyl-palmitoyl)-2-arachidonoyl-GPE (P-16:0/20:4), 1-(1-enyl-stearoyl)-2-arachidonoyl-GPE (P-18:0/20:4), 1-(1-enyl-palmitoyl)-2-arachidonoyl-GPC (P-16:0/20:4), sulfate, and γ-glutamylalanine. Conclusions Among patients with chronic kidney disease, an untargeted serum metabolomics platform identified multiple pathways and metabolites associated with dietary protein intake. Further research is necessary to characterize unknown compounds and to examine these metabolites in association with dietary protein intake among individuals without kidney disease. This trial was registered at clinicaltrials.gov as NCT03202914.

Plasma Insulin and Amino Acid Concentrations in Rats Given an Adequate or Low Protein Diet

1973 ◽  
Vol 103 (5) ◽  
pp. 720-729 ◽  
Author(s):  
Vernon R. Young ◽  
Gaston Vilaire ◽  
Paul M. Newberne ◽  
Robert B. Wilson
Keyword(s):  
Amino Acid ◽  
Plasma Insulin ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Low Protein ◽  
Amino Acid Concentrations

scholarly journals The regulation of protein synthesis in the liver of rats. Mechanisms of dietary amino acid control in the immature animal

1968 ◽  
Vol 107 (5) ◽  
pp. 615-623 ◽  
Author(s):  
R. W. Wannemacher ◽  
W. K. Cooper ◽  
M. B. Yatvin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Specific Radioactivity ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Deficient Diet ◽  
Low Protein ◽  
Rna Content ◽  
Cytoplasmic Rna

Weanling (23-day-old) rats were fed either on an amino acid-deficient diet (6% of casein, which in effect represents an ‘amino acid-deficient’ diet) or on a diet containing an adequate amount of protein (18% of casein) for 28 days. The hepatic cells from the animals fed on the low-protein diet were characterized by low amino acid content, almost complete inhibition of cell proliferation and a marked decrease in cell volume, protein content and concentration of cytoplasmic RNA compared with cells from control rats. The lower concentration of cytoplasmic RNA was correlated with a decreased ribosomal-RNA content, of which a larger proportion was in the form of free ribosomes. The protein-synthetic competence and messenger-RNA content of isolated ribosomes from liver cells of protein-deprived animals were 40–50% of those noted in controls. At 1hr. after an injection of radioactive uridine, the specific radioactivity of liver total RNA was greater in the group fed on the low-protein diet, but the amount of label that was associated with cytoplasmic RNA or ribosomes was significantly less than that noted in control animals. From these data it was concluded that dietary amino acids regulate hepatic protein synthesis (1) by affecting the ability of polyribosomes to synthesize protein and (2) by influencing the concentration of cytoplasmic ribosomes. It is also tentatively hypothesized that the former process may be directly related to the concentration of cellular free amino acids, whereas the latter could be correlated with the ability of newly synthesized ribosomal sub-units to leave the nucleus.

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