PP111 - PROLONGED HYPERAMINOACIDEMIA ELICITS A SUSTAINED SKELETAL MUSCLE ANABOLIC RESPONSE IN HEALTHY MALES
PP111
PROLONGED HYPERAMINOACIDEMIA ELICITS A SUSTAINED SKELETAL MUSCLE ANABOLIC RESPONSE IN HEALTHY MALES
N. Boot1,*, L. M. Kuin1, J. M. Malowany1, A. Zorenc1, E. Kornips1, R. Mohren1, J. Senden1, M. C. van de Poll2, J. Trommelen1, L. B. Verdijk1, L. J. van Loon1
1Human Biology, Maastricht University, 2Department of Intensive Care Medicine, Maastricht University Medical Centre+, Maastricht, Netherlands
Rationale: The muscle anabolic response to protein ingestion is transient, typically lasting a few hours. Whether sustained amino acid provision, as applied with (par)enteral nutrition, can prolong this muscle anabolic response remains unclear. Therefore, this study examined changes in muscle protein synthesis rates during prolonged hyperaminoacidemia following continuous amino acid infusion in healthy males.
Methods: Ten healthy males (23±5 y; 21.1±2.5 kg/m2) received primed, continuous infusions of L-[ring-13C6]-phenylalanine and L-[3,5-2H2]-tyrosine for 11 h. Following assessment of post-absorptive muscle protein synthesis rates, a primed, continuous peripheral intravenous infusion of amino acids (228 mg/kg/h) was administered for 8 h. Blood and muscle samples were collected every 2 h during amino acid administration to assess plasma total amino acid (TAA) concentrations and myofibrillar protein synthesis (MyoPS) rates. Data were analysed by linear mixed models.
Results: In the post-absorptive state, plasma TAA concentrations and MyoPS rates averaged 1841±95 µmol/L and 0.025±0.010 %/h, respectively. Following the onset of continuous amino acid infusion, plasma TAA concentrations increased to 4544±71 µmol/L and remained elevated throughout the entire 8 h feeding period (all P<0.05 vs post-absorptive). MyoPS increased following the onset of amino acid administration with rates averaging 0.054±0.019, 0.041±0.018, 0.072±0.035 and 0.066±0.039 %/h over the 0-2, 2-4, 4-6 and 6-8 h time frames, respectively. MyoPS rates, assessed over the entire 8 h period, averaged 0.058±0.013 %/h (P<0.001, vs post-absorptive values).
Conclusion: Skeletal muscle protein synthesis rates increase following intravenous amino acid administration and remain elevated under conditions of continued hyperaminoacidemia.
Disclosure of Interest: N. Boot: None declared, L. Kuin: None declared, J. Malowany: None declared, A. Zorenc: None declared, E. Kornips: None declared, R. Mohren: None declared, J. Senden: None declared, M. van de Poll Other: received in-kind research support and consultancy fees from Nutricia, J. Trommelen Grant / Research Support from: received research funding from Nutricia-Danone for studies on enteral nutrition unrelated to this work, L. Verdijk Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism., L. van Loon Other: received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon