Kubo Ken-Ichiro, Deguchi Kimiko
Department of Anatomy, Keio University School of Medicine, Tokyo, Japan.
Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.
J Obstet Gynaecol Res. 2020 Nov;46(11):2242-2250. doi: 10.1111/jog.14468. Epub 2020 Sep 13.
Recent advances in perinatal and neonatal medicine have resulted in marked improvements in the survival rates of extremely preterm infants (born before 28 gestational weeks) around the world, and Japan is among the countries with the highest reported survival rates of extremely preterm infants. However, it remains a major concern that many survivors develop neurodevelopmental disabilities, including cognitive dysfunctions and neurodevelopmental disorders later in life. In order to understand the pathophysiological mechanisms underlying the neurodevelopmental disabilities observed in the survivors of extremely preterm births, we reviewed recently reported findings about the development of the human neocortex.
First, we have summarized the current knowledge about the development of the neocortex, including recently reported human- and/or primate-specific developmental events. Next, we discussed the possible causal mechanisms underlying the development of neurodevelopmental disabilities in extremely preterm infants.
Around the birth of extremely preterm infants, neurogenesis and succeeding neuronal migrations are ongoing in the neocortex of human brain. Expansion and maturation of the subplate, which is thought to reflect the axonal wiring in the neocortex, is also prominent at this time.
Brain injuries that occur around the birth of extremely preterm infants are presumed to affect the dynamic developmental events in the neocortex, such as neurogenesis, neuronal migrations and maturation of the subplate, which could underlie the neurodevelopmental disabilities that often develop subsequently in extremely preterm infants. These possibilities should be borne in mind while considering maternal and neonatal care to further improve the long-term outcomes of extremely preterm infants.
围产期和新生儿医学的最新进展已使全球极早产儿（孕28周前出生）的存活率显著提高，日本是极早产儿存活率报告最高的国家之一。然而，许多幸存者在日后出现神经发育障碍，包括认知功能障碍和神经发育疾病，这仍是一个主要问题。为了了解极早产幸存者中观察到的神经发育障碍的病理生理机制，我们回顾了最近报道的关于人类新皮质发育的研究结果。
首先，我们总结了目前关于新皮质发育的知识，包括最近报道的人类和/或灵长类动物特有的发育事件。接下来，我们讨论了极早产儿神经发育障碍发生的可能因果机制。
在极早产儿出生前后，人类大脑新皮质中神经发生和随后的神经元迁移仍在进行。此时，被认为反映新皮质轴突布线的亚板层的扩展和成熟也很显著。
极早产儿出生前后发生的脑损伤被认为会影响新皮质中的动态发育事件，如神经发生、神经元迁移和亚板层成熟，这可能是极早产儿随后经常出现神经发育障碍的基础。在考虑母婴护理以进一步改善极早产儿的长期预后时，应牢记这些可能性。
