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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #319378
Title: Leucine is a major regulator of muscle protein synthesis in neonates

Author
item COLUMBUS, DANIEL - Children'S Nutrition Research Center (CNRC)
item FIOROTTO, MARTA - Children'S Nutrition Research Center (CNRC)
item DAVIS, TERESA - Children'S Nutrition Research Center (CNRC)

Submitted to: Amino Acids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2014
Publication Date: 11/20/2014
Citation: Columbus, D.A., Fiorotto, M.L., Davis, T.A. 2014. Leucine is a major regulator of muscle protein synthesis in neonates. Amino Acids. 47(2):259-270.

Interpretive Summary: Approximately 10% of infants born in the United States are of low birth weight. Due to their inability to tolerate normal feeding, reduced growth in the neonatal period is a common occurrence leading to increased risk of health issues in later life. An improved understanding of how dietary nutrients affect growth during this critical period of development is vital for the development of strategies to improve survivability and long-term health of low birth weight infants. Previous studies in the pig have demonstrated that muscle protein growth is increased substantially with the intake of food and that this is due to the increase of nutrient signals, such as amino acids, following the meal. Further studies have determined that leucine, in particular, as well as its metabolites, have the unique ability to increase muscle protein synthesis when supplemented in the diet or infused intravenously. Leucine has been evaluated extensively for its ability to enhance muscle protein synthesis with low protein diets, a situation common in low birth weight infants due to an inability to handle complete protein meals. Therefore, leucine is an ideal candidate for inclusion in nutrition programs given its potential to improve growth in low birth weight infants whose growth has been compromised.

Technical Abstract: Approximately 10 % of infants born in the United States are of low birth weight. Growth failure during the neonatal period is a common occurrence in low birth weight infants due to their inability to tolerate full feeds, concerns about advancing protein supply, and high nutrient requirements for growth. An improved understanding of the nutritional regulation of growth during this critical period of postnatal growth is vital for the development of strategies to improve lean gain. Past studies with animal models have demonstrated that muscle protein synthesis is increased substantially following a meal and that this increase is due to the postprandial rise in amino acids as well as insulin. Both amino acids and insulin act independently to stimulate protein synthesis in a mammalian target of rapamycin-dependent manner. Further studies have elucidated that leucine, in particular, and its metabolites, a-ketoisocaproic acid and Beta-hydroxy-Beta-methylbutyrate, have unique anabolic properties. Supplementation with leucine, provided either parenterally or enterally, has been shown to enhance muscle protein synthesis in neonatal pigs, making it an ideal candidate for stimulating growth of low birth weight infants.