Impact of Development on Protein Utilization and Growth

描述（申请人提供）：尽管过去十年低出生体重 (LBW) 婴儿的营养管理有所改善，但大多数出生时体重 <1500 克的婴儿，即使出生时的体型适合胎龄，出院时（大约经龄后 36 周）体重也低于或低于宫内标准的第 10 个百分位数，并且许多人直到青春期和成年初期体重仍然较小。虽然早期生长障碍的后果尚不清楚，但有证据表明，它可能导致该人群发育缺陷的高发生率。提出研究来检验这样的假设：人类婴儿在生长过程中能够最大限度地利用蛋白质的时间是有限的。根据对婴儿的有限研究和对动物的急性研究，这一时期似乎涵盖妊娠后期和产后最初几个月，但仍不确定。推论假设也将在人类婴儿中进行测试，即在对蛋白质摄入敏感性增强的有限时间内最大限度地摄入蛋白质将改善生长，从而减少早产儿随后的生长和神经发育缺陷。总而言之，拟议的研究将确定是否存在一个有限时期，在此期间人类新生儿可以最大限度地利用蛋白质摄入来促进生长（通过全身蛋白质周转来衡量），并将定义该时期。他们还将确定在这段有限的时间内最大限度地增加蛋白质摄入量是否可以改善早期生长，而不会造成不可接受的代谢后果，以及这种改善的生长是否会减少随后的生长和神经发育缺陷。总体而言，该项目的研究结果预计将有助于进一步改善营养管理，从而改善低出生体重婴儿的结局。

DESCRIPTION (provided by applicant): Despite improvements in nutritional management of low birth weight (LBW) infants over the past decade, most who weigh <1500g at birth, even if appropriate size for gestational age at birth, weigh less than and are shorter than the 10th percentiles of intrauterine standards at discharge (approximately 36 wks post menstrual age) and many remain small as late as adolescence and young adulthood. While the consequences of the early growth failure are not known with certainty, there is evidence that it may contribute to the high prevalence of developmental deficits in this population. Studies are proposed to test the hypothesis that there is a finite period during which the human infant is capable of maximal utilization of protein for growth. Based on limited studies in infants and acute studies in animals, this period appears to encompass the latter part of gestation and the first few months post-term but it remains undefined. Corollary hypotheses, which also will be tested in human infants, are that maximizing protein intake during this finite period of enhanced sensitivity to protein intake will improve growth and, hence, reduce the subsequent growth and neurodevelopmental deficits of preterm infants. In toto, the proposed studies will determine if there is a finite period during which the human neonate can maximally utilize protein intake for growth as measured by whole body protein turnover and also will define this period. They also will determine if maximizing protein intake during this finite period improves early growth without imposing unacceptable metabolic consequences and if this improved growth reduces subsequent growth and neurodevelopmental deficits. Overall, the findings of this project are expected to contribute to further improvements in nutritional management and, hence, outcome of LBW infants.