Regulation of skeletal muscle protein synthesis in the preterm pig by intermittent leucine pulses during continuous parenteral feeding.

Autor: Rudar M; Department of Animal Sciences, Auburn University, Auburn, Alabama, USA., Suryawan A; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Nguyen HV; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Chacko SK; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Vonderohe C; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Stoll B; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Burrin DG; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Fiorotto ML; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA., Davis TA; USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA.
Jazyk: angličtina
Zdroj: JPEN. Journal of parenteral and enteral nutrition [JPEN J Parenter Enteral Nutr] 2023 Feb; Vol. 47 (2), pp. 276-286. Date of Electronic Publication: 2022 Oct 10.
DOI: 10.1002/jpen.2450
Abstrakt: Background: Extrauterine growth restriction is a common complication of preterm birth. Leucine (Leu) is an agonist for the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signaling pathway that regulates translation initiation and protein synthesis in skeletal muscle. Previously, we showed that intermittent intravenous pulses of Leu to neonatal pigs born at term receiving continuous enteral nutrition increases muscle protein synthesis and lean mass accretion. Our objective was to determine the impact of intermittent intravenous pulses of Leu on muscle protein anabolism in preterm neonatal pigs administered continuous parenteral nutrition.
Methods: Following preterm delivery (on day 105 of 115 gestation), pigs were fitted with umbilical artery and jugular vein catheters and provided continuous parenteral nutrition. Four days after birth, pigs were assigned to receive intermittent Leu (1600 µmol kg -1  h -1 ; n = 8) or alanine (1600 µmol kg -1  h -1 ; n = 8) parenteral pulses every 4 h for 28 h. Anabolic signaling and fractional protein synthesis were determined in skeletal muscle.
Results: Leu concentration in the longissimus dorsi and gastrocnemius muscles increased in the leucine (LEU) group compared with the alanine (ALA) group (P < 0.0001). Despite the Leu-induced disruption of the Sestrin2·GATOR2 complex, which inhibits mTORC1 activation, in these muscles (P < 0.01), the abundance of mTOR·RagA and mTOR·RagC was not different. Accordingly, mTORC1-dependent activation of 4EBP1, S6K1, eIF4E·eIF4G, and protein synthesis were not different in any muscle between the LEU and ALA groups.
Conclusion: Intermittent pulses of Leu do not enhance muscle protein anabolism in preterm pigs supplied continuous parenteral nutrition.
(© 2022 American Society for Parenteral and Enteral Nutrition.)
Databáze: MEDLINE
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