Schneider Juliane, Miller Steven P
Department of Woman-Mother-Child, Clinic of Neonatology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
Division of Neurology and Centre for Brain and Mental Health, Hospital for Sick Children, Toronto, ON, Canada.
Handb Clin Neurol. 2019;162:155-172. doi: 10.1016/B978-0-444-64029-1.00007-2.
Despite the advances in neonatal intensive care, the preterm brain remains vulnerable to white matter injury (WMI) and disruption of normal brain development (i.e., dysmaturation). Compared to severe cystic WMI encountered in the past decades, contemporary cohorts of preterm neonates experience milder WMIs. More than destructive lesions, disruption of the normal developmental trajectory of cellular elements of the white and the gray matter occurs. In the acute phase, in response to hypoxia-ischemia and/or infection and inflammation, multifocal areas of necrosis within the periventricular white matter involve all cellular elements. Later, chronic WMI is characterized by diffuse WMI with aberrant regeneration of oligodendrocytes, which fail to mature to myelinating oligodendrocytes, leading to myelination disturbances. Complete neuronal degeneration classically accompanies necrotic white matter lesions, while altered neurogenesis, represented by a reduction of the dendritic arbor and synapse formation, is observed in response to diffuse WMI. Neuroimaging studies now provide more insight in assessing both injury and dysmaturation of both gray and white matter. Preterm brain injury remains an important cause of neurodevelopmental disabilities, which are still observed in up to 50% of the preterm survivors and take the form of a complex combination of motor, cognitive, and behavioral concerns.
尽管新生儿重症监护取得了进展，但早产儿的大脑仍然容易受到白质损伤（WMI）和正常脑发育中断（即发育异常）的影响。与过去几十年中遇到的严重囊性WMI相比，当代早产儿队列经历的WMI较轻。除了破坏性病变外，白质和灰质细胞成分的正常发育轨迹也会受到破坏。在急性期，作为对缺氧缺血和/或感染及炎症的反应，脑室周围白质内的多灶性坏死区域累及所有细胞成分。后来，慢性WMI的特征是弥漫性WMI，伴有少突胶质细胞异常再生，这些少突胶质细胞无法成熟为有髓少突胶质细胞，导致髓鞘形成障碍。经典的完全神经元变性伴随着坏死性白质病变，而在弥漫性WMI的反应中，观察到以树突分支和突触形成减少为代表的神经发生改变。神经影像学研究现在为评估灰质和白质的损伤及发育异常提供了更多见解。早产儿脑损伤仍然是神经发育障碍的一个重要原因，在高达50%的早产幸存者中仍然可以观察到，其表现为运动、认知和行为问题的复杂组合。
