Jaffe R
Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, New York, USA.
J Perinat Med. 1998;26(3):168-74.
Progressive development of embryonal and maternal circulations is essential for normal pregnancy outcome. The early embryo and trophoblast are very sensitive to the conditions under which they grow and differentiate. The most crucial event in human ontogeny is trophoblast invasion, a process that will enable chorionic and maternal circulations to develop in a synchronized fashion, balancing the metabolic needs with the capability to defend against oxidative stress. Trophoblast invasion transforms the spiral arteries into low resistance vessels, a change necessary for establishment of continuous forward blood flow once the villi are anchored and have obtained defense mechanisms against oxidative insult. Based on a review of current knowledge of human trophoblast and embryonic growth and development of embryonic and maternal placental circulations it seems that human ontogeny occurs in a low oxygen environment during the initial stages of pregnancy. This is similar to the environment in which the first single cell organisms appeared and it remains to be seen if the development process of the primitive single cell organisms, and its energy generating processes, is an appropriate model for studying early human ontogeny.
胚胎循环和母体循环的逐步发展对于正常的妊娠结局至关重要。早期胚胎和滋养层对其生长和分化的条件非常敏感。人类个体发育中最关键的事件是滋养层侵袭，这一过程能使绒毛膜循环和母体循环以同步方式发展，在代谢需求与抵御氧化应激的能力之间取得平衡。滋养层侵袭将螺旋动脉转变为低阻力血管，一旦绒毛锚定并获得抗氧化损伤的防御机制，这种变化对于建立持续向前的血流是必要的。基于对人类滋养层以及胚胎和母体胎盘循环的胚胎生长发育的现有知识的综述，似乎人类个体发育在妊娠初期处于低氧环境中。这类似于第一个单细胞生物出现的环境，原始单细胞生物的发育过程及其能量产生过程是否是研究早期人类个体发育的合适模型还有待观察。
