METABOLIC CONSEQUENCES OF GROWTH FAILURE IN EXTREMELY LOW BIRTH WEIGHT INFANTS

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。尽管存活率不断提高，早产极低出生体重儿（ELBW）的生长结果仍然非常差。生长障碍在这些婴儿中几乎是普遍的，因为他们接近足月妊娠。高蛋白质损失率和高能量消耗未得到足够营养摄入的补偿似乎是产生这种生长失败的主要因素，可能产生代谢变化，使生存优先于生长。本研究的目的是检验以下总体假设，即子宫外环境的营养不足诱导ELBW婴儿在蛋白质代谢、能量消耗、胰岛素敏感性和内皮功能方面的适应性反应，这些反应在整个婴儿期持续存在。研究将在足月妊娠、4月龄和18月龄的ELBW和正常对照婴儿中进行。具体目标如下：1.评估ELBW婴儿在整个婴儿期肠内喂养期间以及对蛋白质摄入量增加的反应中的蛋白质动力学和蛋白质代谢。2.测定ELBW婴儿在整个婴儿期的总能量消耗率、静息能量消耗率和活动能量消耗率。3.检测ELBW婴儿整个婴儿期的胰岛素敏感性。4.评价超低出生体重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，并为未来更彻底地探索这些适应的潜在机制提供机会。

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.