Reynolds L P, Redmer D A
Department of Animal & Range Sciences, and Cell Biology Center, North Dakota State University, Fargo, North Dakota 58105-5727, USA.
Biol Reprod. 2001 Apr;64(4):1033-40. doi: 10.1095/biolreprod64.4.1033.
The mammalian placenta is the organ through which respiratory gases, nutrients, and wastes are exchanged between the maternal and fetal systems. Thus, transplacental exchange provides for all the metabolic demands of fetal growth and development. The rate of transplacental exchange depends primarily on the rates of uterine (maternal placental) and umbilical (fetal placental) blood flows. In fact, increased uterine vascular resistance and reduced uterine blood flow can be used as predictors of high risk pregnancies and are associated with fetal growth retardation. The rates of placental blood flow, in turn, are dependent on placental vascularization, and placental angiogenesis is therefore critical for the successful development of viable, healthy offspring. Recent studies, including gene knockouts in mice, indicate that the vascular endothelial growth factors represent a major class of placental angiogenic factors. Other angiogenic factors, such as the fibroblast growth factors or perhaps the angiopoietins, also may play important roles in placental vascularization. In addition, recent observations suggest that these angiogenic factors interact with the local vasodilator nitric oxide to coordinate placental angiogenesis and blood flow. In the future, regulators of angiogenesis that are currently being developed may provide novel and powerful methods to ensure positive outcomes for most pregnancies.
哺乳动物的胎盘是母体和胎儿系统之间进行呼吸气体、营养物质和废物交换的器官。因此，经胎盘交换满足了胎儿生长发育的所有代谢需求。经胎盘交换的速率主要取决于子宫（母体胎盘）和脐（胎儿胎盘）血流的速率。事实上，子宫血管阻力增加和子宫血流减少可作为高危妊娠的预测指标，并与胎儿生长受限有关。胎盘血流速率反过来又取决于胎盘血管形成，因此胎盘血管生成对于发育出存活、健康的后代至关重要。包括小鼠基因敲除在内的近期研究表明，血管内皮生长因子是胎盘血管生成因子的主要类别。其他血管生成因子，如成纤维细胞生长因子或可能还有血管生成素，也可能在胎盘血管形成中发挥重要作用。此外，近期观察结果表明，这些血管生成因子与局部血管舒张剂一氧化氮相互作用，以协调胎盘血管生成和血流。未来，目前正在研发的血管生成调节剂可能会提供新颖且强大的方法，以确保大多数妊娠能有良好结局。
