Impact of Development on Protein Utilization and Growth

描述（由申请人提供）：尽管在过去十年中，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<1500g的婴儿，即使出生时的尺寸与胎龄相符，在出院时（大约月经后36周）体重低于或低于子宫内标准的第10百分位，许多婴儿直到青春期和青年期仍体重不足。虽然早期生长衰竭的后果尚不确定，但有证据表明，它可能导致这一人群中发育缺陷的高发。提出的研究是为了验证人类婴儿能够最大限度地利用蛋白质生长的有限时期的假设。根据对婴儿的有限研究和对动物的急性研究，这一时期似乎包括妊娠后期和产后最初几个月，但它仍然不明确。相应的假设也将在人类婴儿中进行测试，即在对蛋白质摄入增强敏感性的有限时期内，最大限度地摄入蛋白质将促进生长，从而减少早产儿随后的生长和神经发育缺陷。总的来说，拟议的研究将确定是否存在一个有限的时期，在此期间，人类新生儿可以最大限度地利用蛋白质摄入量来生长，这是通过全身蛋白质周转率来衡量的，并将确定这一时期。他们还将确定在这一有限时期内最大限度地摄入蛋白质是否能在不造成不可接受的代谢后果的情况下改善早期生长，以及这种改善的生长是否能减少随后的生长和神经发育缺陷。总的来说，该项目的研究结果有望有助于进一步改善营养管理，从而改善低体重婴儿的结局。

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.