Differential effects of amino acid and ketoacid on protein metabolism in humans

Giordano, Mauro; Castellino, Pietro; Ohno, Agnes; DeFronzo, Ralph A.

doi:10.1016/s0899-9007(99)00211-7

Cited by 4 publications

(4 citation statements)

References 27 publications

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“…In the present study, we observed that after LPD, type 2 diabetic patients had reduced ELF, an index of whole-body proteolysis, associated with a decrease in protein oxidation. This complex metabolic adaptation is somewhat similar to that observed in normal participants during hypoaminoacidaemia [37] and possibly prevents type 2 diabetic patients from developing protein malnutrition after a moderate protein restriction diet. In agreement with this hypothesis, we observed increased serum albumin levels and synthetic rates after LPD in type 2 diabetic patients.…”

Section: Discussionsupporting

confidence: 68%

Effects of dietary protein restriction on albumin and fibrinogen synthesis in macroalbuminuric type 2 diabetic patients

et al. 2007

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Aims/hypothesis Diabetic nephropathy is associated with hypoalbuminaemia and hyperfibrinogenaemia. A lowprotein diet has been recommended in patients with diabetic nephropathy, but its effects on albumin and fibrinogen synthesis are unknown. Methods We compared the effects of a normal (NPD; 1.38± 0.08 g kg −1 day −1 ) or low (LPD; 0.81±0.04 g kg −1 day −1 ) -protein diet on endogenous leucine flux (ELF), albumin and fibrinogen synthesis (L-[5,5,5,-2 H 3 ]leucine infusion), and markers of inflammation in nine type 2 diabetic patients with macroalbuminuria. Six healthy participants on NPD served as control participants. Results In comparison with healthy participants, type 2 diabetic patients on an NPD had similar ELF, reduced serum albumin (38±1.1 vs 42±0.8 g/l; p<0.05), similar fractional synthesis rates (FSR) and absolute synthesis rates (ASR) of albumin, and both increased plasma fibrinogen concentration [10.7±0.6 vs 7.2±0.5 μmol/l (3.64±0.22 vs 2.45±0.18 g/l); p<0.05] and fibrinogen ASR [11.03±1.17 vs 6.0±1.8 μmol 1.73 m −2 day −1 (3.7±0.4 vs 1.9±0.3 g 1.73 m −2 day −1 ); p< 0.01]. After LPD, type 2 diabetic patients had the following changes in comparison with NPD: reduced proteinuria (2.74±0.4 vs 4.51±0.8 g/day; p<0.05), ELF (1.93±0.08 vs 2.11±0.08 μmol kg −1 min −1 ; p<0.05) and total fibrinogen pool; increased serum albumin (42±1 vs 38±1 g/l; p<0.01) and albumin ASR (14.1±1 vs 9.9±1 g 1.73 m −2 day −1 ; p< 0.05); and reduced plasma IL-6 levels, which were correlated with albumin ASR (r=−0.749; p<0.05). Conclusions/interpretation LPD in type 2 diabetic patients with diabetic nephropathy reduces low-grade inflammatory state, proteinuria, albuminuria, whole-body proteolysis and ASR of fibrinogen, while increasing albumin FSR, ASR and serum concentration. ISRCTN ID no: CCT-NAPN-16911Keywords Absolute synthesis . Albumin . Diabetic nephropathy . Fibrinogen . Fractional synthesis . Leucine . Low-grade inflammation . Low-protein diet . Macroalbuminuria . Type 2 diabetes Abbreviations ASR absolute synthesis rate CRP C-reactive protein ELF endogenous leucine flux FSR fractional synthesis rate KIC α-ketoisocaproic acid LPD low-protein diet Diabetologia (2008) 51:21-28

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Section: Discussionsupporting

confidence: 68%

Effects of dietary protein restriction on albumin and fibrinogen synthesis in macroalbuminuric type 2 diabetic patients

et al. 2007

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“…A lower bioavailability may suggest that BCKAs do not stimulate muscle protein synthesis to a similar extent when compared with BCAAs or intact protein. Furthermore, it has been observed that intravenous infusion of BCKAs does not stimulate whole-body protein synthesis (32). However, it is important to note that whole-body protein synthesis is not necessarily reflective of muscle protein synthesis and evidence from animal work in fact supports a role for BCKAs as a nutrient regulator of muscle protein synthesis (33, 34).…”

Section: Introductionmentioning

confidence: 99%

Branched-chain amino acid and branched-chain ketoacid ingestion increases muscle protein synthesis rates in vivo in older adults: a double-blind, randomized trial

Fuchs

Hermans

Holwerda

et al. 2019

The American Journal of Clinical Nutrition

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Background Protein ingestion increases muscle protein synthesis rates. However, limited data are currently available on the effects of branched-chain amino acid (BCAA) and branched-chain ketoacid (BCKA) ingestion on postprandial muscle protein synthesis rates. Objective The aim of this study was to compare the impact of ingesting 6 g BCAA, 6 g BCKA, and 30 g milk protein (MILK) on the postprandial rise in circulating amino acid concentrations and subsequent myofibrillar protein synthesis rates in older males. Methods In a parallel design, 45 older males (age: 71 ± 1 y; BMI: 25.4 ± 0.8 kg/m2) were randomly assigned to ingest a drink containing 6 g BCAA, 6 g BCKA, or 30 g MILK. Basal and postprandial myofibrillar protein synthesis rates were assessed by primed continuous l-[ring-13C6]phenylalanine infusions with the collection of blood samples and muscle biopsies. Results Plasma BCAA concentrations increased following test drink ingestion in all groups, with greater increases in the BCAA and MILK groups compared with the BCKA group (P < 0.05). Plasma BCKA concentrations increased following test drink ingestion in all groups, with greater increases in the BCKA group compared with the BCAA and MILK groups (P < 0.05). Ingestion of MILK, BCAA, and BCKA significantly increased early myofibrillar protein synthesis rates (0–2 h) above basal rates (from 0.020 ± 0.002%/h to 0.042 ± 0.004%/h, 0.022 ± 0.002%/h to 0.044 ± 0.004%/h, and 0.023 ± 0.003%/h to 0.044 ± 0.004%/h, respectively; P < 0.001), with no differences between groups (P > 0.05). Myofibrillar protein synthesis rates during the late postprandial phase (2–5 h) remained elevated in the MILK group (0.039 ± 0.004%/h; P < 0.001), but returned to baseline values following BCAA and BCKA ingestion (0.024 ± 0.005%/h and 0.024 ± 0.005%/h, respectively; P > 0.05). Conclusions Ingestion of 6 g BCAA, 6 g BCKA, and 30 g MILK increases myofibrillar protein synthesis rates during the early postprandial phase (0–2 h) in vivo in healthy older males. The postprandial increase following the ingestion of 6 g BCAA and BCKA is short-lived, with higher myofibrillar protein synthesis rates only being maintained following the ingestion of an equivalent amount of intact milk protein. This trial was registered at Nederlands Trial Register (www.trialregister.nl) as NTR6047.

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“…Amino acids (AA) and insulin (INS) play a major role in promoting postprandial (PP) protein anabolism [1][2][3][4]. In vitro studies have shown that INS and AA can independently regulate skeletal muscle protein synthesis and degradation [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Lysosomal and proteasome-dependent proteolysis are differentially regulated by insulin and/or amino acids following feeding in young, mature and old rats

Capel

Prod'Homme

Béchet

et al. 2009

The Journal of Nutritional Biochemistry

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Differential effects of amino acid and ketoacid on protein metabolism in humans

Cited by 4 publications

References 27 publications

Effects of dietary protein restriction on albumin and fibrinogen synthesis in macroalbuminuric type 2 diabetic patients

Effects of dietary protein restriction on albumin and fibrinogen synthesis in macroalbuminuric type 2 diabetic patients

Branched-chain amino acid and branched-chain ketoacid ingestion increases muscle protein synthesis rates in vivo in older adults: a double-blind, randomized trial

Lysosomal and proteasome-dependent proteolysis are differentially regulated by insulin and/or amino acids following feeding in young, mature and old rats

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