OMEGA-3 FATTY ACIDS AND VISUAL DEVELOPMENT

描述：大多数婴儿配方奶粉都含有丰富的α-亚麻酸(LNA)。 但是配方奶粉喂养的婴儿有患二十二碳六烯酸(DHA)的风险。 由于它们代谢这一长链的能力有限而导致的缺陷 生命最初几个月来自LNA的多不饱和脂肪酸(LCP)。 配方奶喂养的婴儿红细胞脂肪酸组成异常， 与母乳喂养的婴儿相比，他们的视网膜和大脑 通过母乳预制的DHA。配方奶喂养的婴儿，他们的饮食既缺乏又缺乏 LNA和DHA表现出较不敏感的视杆细胞视网膜电图(ERG)功能， 皮质视觉诱发电位(VEP)视力越差，越差 优先(PL)敏锐度，在费根和贝利上得分较低 测试。早产儿和足月儿对膳食DHA的特殊需求是 本赠款期间的研究重点和PI中期成果 支持DHA对视觉功能最佳成熟的重要性。 1.阐明DHA在支持玉米最适成熟中的作用 皮质功能。VEP，特别是PL敏感度已被广泛用于 大脑皮层或中枢神经系统普遍成熟的指标； 这些研究的动机一直是微妙的量化 差异与神经膜的LCP组成有关。私生党提议 通过随机方法更直接地评估皮质功能的一系列研究 39周、4周进行点立体视和认知功能测试 三岁零九岁。这些数据与VEP和PL视力数据相结合， 也将被用来检验VEP和PL假设的有效性 敏感度通过并发分析提供皮质成熟的指标 和认知表现的预测效度。 2.评估早期饮食补充的必要性 断奶了。基于我们的数据，这些数据支持DHA在 学期饮食，我们将解决DHA是否在 断奶后饮食。在美国，通常的做法是在短短6-8周内 母乳喂养；然而，初步证据表明，饮食供应 DHA在至少17周内是必不可少的。这项研究将是第一次测试 DHA在断奶后饮食中的重要性 随机试验。3.评价DHA在神经中的功能作用 人类婴儿的视网膜膜。虽然已经有了一些 DHA在脊椎动物神经膜中作用的研究，很少是 已知DHA在人类婴儿神经膜中的作用。 日粮中添加DHA对激活和失活的功能影响 光转导级联的时相和突触效率 光-受体-双极连接将在 随机试验。这些数据将为这一假设提供第一次检验 神经膜脂肪酸组成的变化导致改变 人类婴儿的转导和神经传递。 4.评价婴儿体内和体内合成DHA的能力 体外培养。根据PI最近的发现，体内的伸长/去饱和 婴儿必需脂肪酸(EFAs)的含量是有限的，他计划评估 胎儿生长发育、胎龄和饮食对体内EFA的影响 转换。体内研究将得到体外研究的补充。 胎儿视网膜组织中LCP生物合成随时间的变化 培养、胎龄和脂肪酸底物。来自体内的数据 体外研究将有助于确定内源性LCP生物合成 常规婴儿和特殊婴儿的营养能力和最佳脂肪组成 公式。

DESCRIPTION: Most infant formulas provide ample alpha-linolenic acid (LNA) but formula fed infants are at risk for docosahexaenoic acid (DHA) deficiency due to their limited ability to metabolize this long-chain polyunsaturated fatty acid (LCP) from LNA during the first months of life. Formula-fed infants have abnormal fatty acid composition of red blood cells, retina and brain when compared with breast-fed infants, who obtain pre-formed DHA via human milk. Formula-fed infants whose diets lack both LNA and DHA exhibit less sensitive rod electroretinographic (ERG) function, poorer cortical visual evoked potential (VEP) acuity, poorer preferential-looking (PL) acuity, and lower scores on Fagan and Bayley tests. A specific need for dietary DHA in preterm and term infants is the focus of studies during the current grant period and the PI interim results support the essentiality of DHA for optimal maturation of visual function. 1. To delineate the role of DHA in supporting optimal maturation of cortical function. VEP and especially PL acuity have been widely used as indices of general maturation of the cortex or central nervous system; the motivation for these studies has been the quantification of subtle differences related to LCP composition of neural membranes. The PI proposes a series of studies to more directly evaluate cortical function via random dot stereoacuity and tests of cognitive function administered at 39 weeks, 4 years and 9 years of age. These data, coupled with VEP and PL acuity data, will also be used to examine the validity of the hypothesis that VEP and PL acuity provide indices of cortical maturation through analyses of concurrent and predictive validity for cognitive performance. 2. To evaluate the need for dietary supplementation following early weaning. Based on our data which support the essentiality of DHA in the term diet, we will address the question of whether DHA is essential in the post-weaning diet. Common practice in the US is a short 6-8 week period of breast-feeding; yet preliminary evidence suggests that a dietary supply of DHA is essential for at least 17 weeks. This study will be the first test of the essentiality of DHA in the post-weaning diet in the context of a randomized trial. 3. To evaluate the functional role of DHA in the neural retinal membranes of human infants. While there have been a number of studies on the role of DHA in neural membranes in vertebrates, little is known about the role of DHA in the neural membranes of the human infant. The functional effects of dietary DHA supply on activation and inactivation phases of the phototransduction cascade and the synaptic efficiency of the photo-receptor-bipolar junction will be evaluated in the context of a randomized trial. These data will provide the first test of the hypothesis that changes in neural membrane fatty acid composition lead to altered transduction and neurotransmission in the human infant. 4. To assess the capacity of human infants to synthesize DHA in vivo and in vitro. Based on the PI recent finding that in vivo elongation/desaturation of essential fatty acids (EFAs) in infants is limited, he plans to evaluate the impact of fetal growth, gestational age and diet on in vivo EFA conversion. in vivo studies will be complemented by in vitro investigations of LCP biosynthesis in fetal retinal tissue as a function of time in culture, gestational age and fatty acid substrate. Data from the in vivo and in vitro studies will assist in defining endogenous LCP biosynthetic capacity and optimal lipid composition for routine and specialty infant formulas.