Nutritionally Regulated Hormonal Factors in Prolonged Postnatal Growth Retardation and Its Associated Adverse Neurodevelopmental Outcome in Extreme Prematurity

Abstract

Recent published data show that at hospital discharge, most infants born at <30 weeks of gestation would not achieve the median birth weight of the reference fetus at the same postconceptional age, and many would be less than the 10th centile. Estimating from the current recommendations of calorie and protein intakes, these infants accrue large deficits in intakes of protein and calorie during the first weeks of life. Postnatal growth retardation over a prolonged period of time is related to neurodevelopmental delays. While a total energy intake of 120 kcal/kg/day has generally been considered adequate, protein requirement in low gestation infants remains a matter for debate. Increasing the dietary protein:calorie ratio has previously been proposed as a strategy to enhance growth and to achieve a body composition similar to that of the reference fetus. Previous study data reveal that serum insulin-like growth factor I (IGF-I) concentration is positively correlated with protein intake, and nitrogen retention, in turn, is positively correlated with serum IGF-I concentration. Remarkably, elevated serum growth hormone but low serum IGF-I concentrations have been reported in low gestation infants and in infants with intrauterine growth retardation, suggesting IGF-I being a nutritionally regulated hormonal factor in the postnatal growth retardation. As neurodevelopment in extreme prematurity is likely affected by multiple factors, we hypothesize that a combined strategy of the previously proposed hormonal supplement with hydrocortisone and tri-iodothyronine together with increased dietary protein intake (progressively increasing from 1.5 g/kg/day intravenously administered amino acids immediately after birth, then 3.6 g/100 kcal at ≈125 kcal/kg/day when enterally fed till the infant reaches a body weight of ≧1.8 kg and at ≧50th centile weight of the reference fetus at the same postconceptional age) would likely be synergistic and more effective in improving neurodevelopmental outcome.

Postnatal Head Growth in Preterm Infants: A Randomized Controlled Parenteral Nutrition Study

“…44,45 IGF-I is also modulated by nutritional intake. 46 Our study clearly reveals that the pervasive failure to achieve adequate head growth should be attributed to inadequate nutrition.Complex nutritional interventions are difficult to implement consistently in clinical practice and this creates challenges for study design. Our study specifically focused on the period of maximal PN delivery and was not designed to assess differences in PN before day 3.…”

Plasma Arginine Levels and Blood Glucose Control in Very Preterm Infants Receiving 2 Different Parenteral Nutrition Regimens

“…There may be a wider role for arginine in regulating postnatal growth and metabolism rather than just reducing the risk of very preterm hyperglycemia. The relationship of protein, insulin, insulin‐like growth factor I, and fetal/neonatal growth is well described, 54 although the role of specific AAs is less clear. In this respect, the poor growth demonstrated by arginine‐deficient piglets provides a particularly relevant animal model.…”

The evolution of human fatness and susceptibility to obesity: an ethological approach

“…Dietary protein has been found to influence the level of the hormone insulin-like growth factor 1 (IGF-I) and hence growth rate in infants (Yeung & Smyth, 2003), while rapid infant growth rates have been linked to increased IGF-I and IGF-II levels in children aged five years (Ong et al, 2002). These findings indicate that high protein intake in early life may programme subsequent obesity (Rolland-Cachera et al, 1995).…”