Laboratory of Neuropathology, State Institute of Brain Paulo Niemeyer and Federal University of Rio de Janeiro (UFRJ), Rua do Resende 156, Rio de Janeiro, RJ, CEP 20231-092, Brazil.
Research Institute Prof. Amorim Neto, Rua Duque de Caxias, 330, Prata, Campina Grande, PB, CEP 58400506, Brazil.
Acta Neuropathol. 2017 Jun;133(6):983-999. doi: 10.1007/s00401-017-1699-5. Epub 2017 Mar 22.
A major concern associated with ZIKV infection is the increased incidence of microcephaly with frequent calcifications in infants born from infected mothers. To date, postmortem analysis of the central nervous system (CNS) in congenital infection is limited to individual reports or small series. We report a comprehensive neuropathological study in ten newborn babies infected with ZIKV during pregnancy, including the spinal cords and dorsal root ganglia (DRG), and also muscle, pituitaries, eye, systemic organs, and placentas. Using in situ hybridization (ISH) and electron microscopy, we investigated the role of direct viral infection in the pathogenesis of the lesions. Nine women had Zika symptoms between the 4th and 18th and one in the 28th gestational week. Two babies were born at 32, one at 34 and 36 weeks each and six at term. The cephalic perimeter was reduced in four, and normal or enlarged in six patients, although the brain weights were lower than expected. All had arthrogryposis, except the patient infected at 28 weeks gestation. We defined three patterns of CNS lesions, with different patterns of destructive, calcification, hypoplasia, and migration disturbances. Ventriculomegaly was severe in the first pattern due to midbrain damage with aqueduct stenosis/distortion. The second pattern had small brains and mild/moderate (ex-vacuo) ventriculomegaly. The third pattern, a well-formed brain with mild calcification, coincided with late infection. The absence of descending fibres resulted in hypoplastic basis pontis, pyramids, and cortico-spinal tracts. Spinal motor cell loss explained the intrauterine akinesia, arthrogryposis, and neurogenic muscle atrophy. DRG, dorsal nerve roots, and columns were normal. Lympho-histiocytic inflammation was mild. ISH showed meningeal, germinal matrix, and neocortical infection, consistent with neural progenitors death leading to proliferation and migration disorders. A secondary ischemic process may explain the destructive lesions. In conclusion, we characterized the destructive and malformative consequences of ZIKV in the nervous system, as reflected in the topography and severity of lesions, anatomic localization of the virus, and timing of infection during gestation. Our findings indicate a developmental vulnerability of the immature CNS, and shed light on possible mechanisms of brain injury of this newly recognized public health threat.
与 ZIKV 感染相关的一个主要问题是,感染母亲所生婴儿的小头畸形发病率增加,且常伴有钙化。迄今为止,对先天性感染中枢神经系统(CNS)的尸检分析仅限于个别报告或小系列。我们报告了 10 例在妊娠期间感染 ZIKV 的新生儿的全面神经病理学研究,包括脊髓和背根神经节(DRG),以及肌肉、垂体、眼睛、全身器官和胎盘。我们使用原位杂交(ISH)和电子显微镜研究了病毒直接感染在病变发病机制中的作用。9 名妇女在妊娠第 4 周至第 18 周出现 Zika 症状,1 名在妊娠第 28 周出现症状。2 名婴儿在 32 周时出生,1 名在 34 周时出生,1 名在 36 周时出生,6 名在足月时出生。4 名婴儿头围减小,6 名婴儿头围正常或增大,尽管脑重低于预期。除了在妊娠 28 周时感染的患者外,所有患者均有关节挛缩。我们定义了三种 CNS 病变模式,具有不同的破坏性、钙化、发育不良和迁移障碍模式。由于中脑损伤伴导水管狭窄/变形,第一种模式的脑室明显扩大。第二种模式的脑体积小,脑室轻度/中度扩大(脑外积水)。第三种模式,大脑形态正常,轻度钙化,与晚期感染一致。下行纤维缺失导致脑桥基底部、锥体和皮质脊髓束发育不良。脊髓运动细胞丢失解释了宫内运动障碍、关节挛缩和神经源性肌肉萎缩。背根神经节、背根和柱正常。淋巴组织细胞炎症轻微。ISH 显示脑膜、生发基质和新皮质感染,与神经祖细胞死亡导致增殖和迁移障碍一致。二次缺血过程可能解释了破坏性病变。总之,我们描述了 ZIKV 在神经系统中的破坏性和畸形后果,反映在病变的部位和严重程度、病毒的解剖定位以及妊娠期间感染的时间。我们的发现表明,未成熟的中枢神经系统易受发育影响,并阐明了这种新出现的公共卫生威胁的脑损伤的可能机制。