METABOLIC CONSEQUENCES OF GROWTH FAILURE IN EXTREMELY LOW BIRTH WEIGHT INFANTS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。尽管生存率不断提高，早产儿极低出生体重（ELBW）的生长结果仍然异常差。生长衰竭在这些婴儿中几乎是普遍的，因为他们接近妊娠期。蛋白质的高损失率和能量消耗的增加，没有得到足够的营养摄入的补偿，似乎是造成这种生长失败的主要因素，可能会产生代谢变化，优先考虑生存而不是生长。本研究的目的是验证一种假设，即子宫外环境的营养不足会导致ELBW婴儿在整个婴儿期持续存在的蛋白质代谢、能量消耗、胰岛素敏感性和内皮功能方面的适应性反应。研究将在ELBW和正常对照的足月、4个月和18个月的婴儿中进行。将实现下列具体目标：评估肠内喂养期间的蛋白质动力学和蛋白质分解代谢，以及对低体重婴儿整个婴儿期蛋白质摄入量增加的反应。2. 确定低体重婴儿在整个婴儿期的总能量消耗、静息能量消耗和活动能量的比率。3. 目的：探讨ELBW婴儿整个婴儿期的胰岛素敏感性。4. 评估ELBW婴儿整个婴儿期的内皮功能。这些研究可能为改善这些婴儿的临床和营养策略奠定基础，也为未来更彻底地探索这些适应的潜在机制提供了机会。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Despite continually improving survival rates, growth outcomes for premature extremely low birth weight (ELBW) infants remains exceptionally poor. Growth failure is nearly universal in these infants as they near term gestation. High rates of protein loss and elevated energy expenditures uncompensated by adequate nutritional intake appear to be primary factors in producing this growth failure, perhaps producing metabolic changes that prioritize survival over growth. The goal of the present proposal is to test the overall hypothesis that nutritional inadequacies of the extrauterine environment induce adaptive responses in protein metabolism, energy expenditure, insulin sensitivity, and endothelial function in ELBW infants which persist throughout infancy. Studies will be performed in ELBW and normal control infants at term gestation, 4 and 18 months of age. The following specific aims will be pursued: 1. To assess protein kinetics and protein catabolism during enteral feeding and in response to increased protein intake in ELBW infants throughout infancy. 2. To determine the rate of total energy expenditure, resting energy expenditure, and energy of activity in ELBW infants throughout infancy. 3. To examine insulin sensitivity in ELBW infants throughout infancy. 4. To evaluate endothelial function in ELBW infants throughout infancy. These studies may form the basis for improved clinical and nutritional strategies for these infants, as well as a future opportunity to more thoroughly explore the potential mechanisms underlying these adaptations.