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

Autor: Marko Rudar, Agus Suryawan, Hanh V. Nguyen, Shaji K. Chacko, Caitlin Vonderohe, Barbara Stoll, Douglas G. Burrin, Marta L. Fiorotto, Teresa A. Davis
Rok vydání: 2022
Předmět:
Zdroj: Journal of Parenteral and Enteral Nutrition. 47:276-286
ISSN: 1941-2444
0148-6071
Popis: 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.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 kgLeu 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.Intermittent pulses of Leu do not enhance muscle protein anabolism in preterm pigs supplied continuous parenteral nutrition.
Databáze: OpenAIRE
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