FUNCTIONAL CYTOLOGY OF THE PLACENTA AND FETAL MEMBRANES

在人类和非人类灵长类动物中，绝大多数母胎 交换由胎盘介导。 因此，它具有根本的 了解胎儿营养和新生儿健康的重要性 确定胎盘选择性地 从母体血液中吸收物质并将其运送到 胎儿 分离母体和胎儿血流的主要成分 是：1）合胞滋养层2）基底层和3）胎儿毛细血管。 本提案中包含的实验将研究各种 这些组件中的每一个的结构和功能方面，特别是 因为它们与吸收性和渗透性有关。 受体介 内吞作用是细胞，包括 滋养层从环境中吸收大分子。 这个过程 将通过结合超微结构和生物化学的方法详细检查 方法，以定量地确定各种 配体与滋养层相互作用， 免疫细胞化学方法确定细胞内途径， 配体及其受体。 选择的配体包括IgG，因为 它在为胎儿提供被动免疫方面的重要性，LDL， 它作为激素合成和转铁蛋白前体的重要性， of its role作用in iron铁transport运输to the fetus胎儿. 因为潜在的 细胞骨架在许多细胞功能中的重要作用，包括 内吞作用，其他研究将确定组成和定位 人胎盘主要细胞骨架蛋白的免疫荧光分析 和超微结构免疫细胞化学方法。 除了 大分子，离子运输到发育中的胎儿是另一个 至关重要的胎盘功能 为了更好地理解 与胎盘翼主动离子转运相关亚细胞结构 将定位Na+，K+ ATP酶，Ca++ ATP酶和Ca++在人胎盘中， 超微细胞化学 的结构和功能基础 将研究滋养层和羊膜基底层的渗透性。 分离 基底板层将暴露于示踪蛋白， 基底层的去除将暴露于示踪蛋白， 选择性去除基底层糖胺聚糖，特别是乙酰肝素 以确定这些组分是否影响渗透性。 最后， 胎儿毛细血管床的立体排列 中间的人类和非人类灵长类胎盘绒毛将 为了确定他们的结构组织如何影响 母胎交换

In humans and non-human primates, the vast majority of maternal-fetal exchanges are mediated by the placenta. It is, therefore, of fundamental importance to our understanding of fetal nutritional and neonatal health problems to ascertain the mechanisms by which the placenta selectively absorbs substances from the maternal blood and transports them to the fetus. The major components separating the maternal and fetal bloodstreams are: 1) syncytial trophoblast 2) a basal lamina and 3) fetal capillaries. The experiments encompassed in this proposal will examine various structural and functional aspects of each of these components, especially as they relate to absorption and permeability. Receptor-mediated endocytosis is one important mechanism by which cells, including trophoblast, take up macromolecules from their environment. This process will be examined in detail by combined ultrastructural and biochemical methods in order to quantitatively detemine the manner in which various ligands interact with trophoblast, and ultrastructurally and immunocytochemically to determine the intracellular pathways followed by ligands and their receptors. The ligands selected include IgG, because of its importance in providing passive immunity to the fetus, LDL because of its importance as a precursor for hormone synthesis and transferrin because of its role in iron transport tothe fetus. Because of the potentially important role of the cytoskeleton in many cellular functions, including endocytosis, other studies will determine the composition and localization of major cytoskeletal proteins in human placenta using immunofluorescent and ultrastructural immunocytochemical methods. In addition to macromolecules, the transport of ions to the developing fetus is another vitally important placental function. In order to better understand the subcellular structures associated with active ion transport by placenta we will localize Na+, K+ ATPase, Ca++ ATPase, and Ca++ in human placenta using ultratructural cytochemistry. The structural and functional basis of trophoblast and amnion basal lamina permeability will be studied. Isolated basal laminas will be exposed to tracer proteins with and without selective removal of basal lamina will be exposed to tracer proteins with and without selective removal of basal lamina glycosaminoglycans, particularly heparan sulfate to determine if these components influence permeability. Finally, the three-dimensional arrangement of the fetal capillary bed in terminal and intermediate human and non-human primate placental villi will be examined in order to determine how their structural organization may affect maternal-fetal exchange.