Ovine model system for alcohol related birth defects

说明(申请人提供)：尽管大力教育妇女不要在怀孕期间饮酒，但胎儿酒精谱障碍的发生率并未下降，因此必须了解产前酒精暴露导致神经发育损害的机制，以便制定预防和改善策略。在这项建议中，我们将利用成熟的绵羊模型的独特优势来研究酒精导致脑损伤的基本机制，并开始探索保护策略。我们已经报道，酒精会导致母体和胎儿酸血症，以及母体谷氨酰胺和谷氨酰胺相关代谢物的减少。我们假设酒精介导的酸血症减少了胎儿谷氨酰胺和谷氨酰胺相关的代谢物，这导致或促成了氧化应激和脑损伤的增加。在特定目标1中，我们假设酒精引起母体和胎儿酸中毒，导致胎儿体内谷氨酰胺及其含氮代谢产物浓度的改变。实验1在慢性仪器化的羔羊胚胎中测试了这一假说，以应对急性酒精或酸血症操作，并将确定母亲的谷氨酰胺是否会阻止代谢物浓度的变化。在具体目标2中，我们假设在相当于人脑发育的第三个三个月期间，产前酒精暴露通过导致酸血症、胎儿谷氨酰胺减少和氧化应激增加而起作用。实验2a将确定酒精或酸血症是否会改变孕妇和胎儿脑室内谷氨酰胺及其代谢物的浓度和流量，以及孕妇服用谷氨酰胺是否会阻止这些变化。实验2b将测试酒精在相当于人脑发育的第三个三个月期间pH和谷氨酰胺的降低是否会导致氧化应激增加，以及母亲的谷氨酰胺是否具有预防作用。特定目的3假设母亲给予谷氨酰胺可以预防妊娠晚期同等酒精暴露所致的胎儿脑损伤(实验3检验这一假设)。由于已知酒精通过多种机制起作用，我们预测谷氨酰胺将在很大程度上但不是完全预防脑损伤，这些发现将使我们处于开发实用的、组合的营养预防的极佳地位，这是NIAAA战略计划中规定的目标。与公共卫生的相关性：教育未能显著降低胎儿酒精综合症的发生率，因此必须了解产前酒精暴露造成神经发育损害的机制，以便制定预防和改善策略。在这项建议中，我们测试了几个解释酒精如何导致这种损害的假设，并将测试基于这些假设的营养预防。这项研究涉及国家酒精中毒和酒精滥用研究所战略计划中规定的目标。

DESCRIPTION (provided by applicant): Despite significant efforts to educate women to not drink during pregnancy, the incidence of Fetal Alcohol Spectrum Disorders has not declined making it important to obtain understanding of the mechanisms by which prenatal alcohol exposure causes neurodevelopmental damage in order to develop preventative and ameliorative strategies. In this proposal, we will exploit the unique advantages of the well established sheep model to investigate basic mechanisms by which alcohol causes brain injury and to begin exploring protective strategies. We have reported that alcohol causes maternal and fetal acidemia and reductions in maternal glutamine and glutamine-related metabolites. We hypothesize that alcohol mediated acidemia decreases fetal glutamine and glutamine-related metabolites and that this results in, or contributes to, elevations of oxidative stress and brain injury. In Specific Aim 1, we hypothesize that alcohol induces maternal and fetal acidosis that results in altered concentrations of glutamine and its nitrogenous metabolites in the fetus. Experiment 1 tests this hypothesis in chronically instrumented lamb fetuses in response to acute alcohol or acidemia manipulations and will determine if maternal glutamine will prevent the changes in metabolite concentrations. In Specific Aim 2, we hypothesize that prenatal alcohol exposure throughout the 3rd trimester equivalent of human brain development acts by causing acidemia, reductions in fetal glutamine and increases in oxidative stress. Experiment 2a will determine if alcohol or acidemia alters concentrations of glutamine and its metabolites in, and flux between, maternal and fetal compartments and across the fetal brain and if maternal glutamine administration prevents these changes. Experiment 2b will test whether the alcohol mediated decreases in pH and glutamine throughout the third trimester equivalent of human brain development results in increases in oxidative stress and if maternal glutamine is preventative. Specific aim 3 hypothesizes that maternal glutamine administration will prevent the fetal brain injury in response to 3rd trimester equivalent alcohol exposure (Experiment 3 tests this hypotheis). Because alcohol is known to act through more than one mechanism, we predict that glutamine will substantially but not completely prevent brain injury and that these findings will place us in an excellent position to develop a practical, combinatory, nutritional prevention, a stated goal in the NIAAA strategic plan. PUBLIC HEALTH RELEVANCE: The failure of education to significantly reduce the incidence of Fetal Alcohol Syndrome has made it important to obtain understanding of the mechanisms by which prenatal alcohol exposure causes neurodevelopmental damage in order to develop preventative and ameliorative strategies. In this proposal we test several hypotheses that would explain how alcohol causes this damage and will test a nutritional prevention based on the on these hypotheses. This research addresses a stated goal in the National Institute on Alcoholism and Alcohol Abuse strategic plan.