Maternal SARS-CoV-2, Placental Changes and Brain Injury in 2 Neonates

Abstract

Long-term neurodevelopmental sequelae are a potential concern in neonates following in utero exposure to severe acute respiratory syndrome coronavirus disease 2 (SARS-CoV-2). We report 2 neonates born to SARS-CoV-2 positive mothers, who displayed early-onset (day 1) seizures, acquired microcephaly, and significant developmental delay over time. Sequential MRI showed severe parenchymal atrophy and cystic encephalomalacia. At birth, neither infant was SARS-CoV-2 positive (nasopharyngeal swab, reverse transcription polymerase chain reaction), but both had detectable SARS-CoV-2 antibodies and increased blood inflammatory markers. Placentas from both mothers showed SARS-CoV-2-nucleocapsid protein and spike glycoprotein 1 in the syncytiotrophoblast, fetal vascular malperfusion, and significantly increased inflammatory and oxidative stress markers pyrin domain containing 1 protein, macrophage inflammatory protein 1 βη, stromal cell-derived factor 1, interleukin 13, and interleukin 10, whereas human chorionic gonadotropin was markedly decreased. One infant (case 1) experienced sudden unexpected infant death at 13 months of age. The deceased infant's brain showed evidence of SARS-CoV-2 by immunofluorescence, with colocalization of the nucleocapsid protein and spike glycoprotein around the nucleus as well as within the cytoplasm. The constellation of clinical findings, placental pathology, and immunohistochemical changes strongly suggests that second-trimester maternal SARS-CoV-2 infection with placentitis triggered an inflammatory response and oxidative stress injury to the fetoplacental unit that affected the fetal brain. The demonstration of SARS-CoV-2 in the deceased infant's brain also raises the possibility that SARS-CoV-2 infection of the fetal brain directly contributed to ongoing brain injury. In both infants, the neurologic findings at birth mimicked the presentation of hypoxic-ischemic encephalopathy of newborn and neurologic sequelae progressed well beyond the neonatal period.

FIGURE 1

Neurologic findings in both cases. Case 1, preterm infant, (A) axial T2 weighted brain MRI on day 2, demonstrating T2 hypointensity in the left germinal matrix and dependent portion of the left occipital horn (arrows) and (B) axial T2 weighted brain MRI at 10 weeks, demonstrating significant atrophy of the brain parenchyma. In Case 2, term infant, (C) axial diffusion-weighted imaging from brain MRI done on day 4 demonstrates increased diffusion signal consistent with restricted diffusion, involving the entire supratentorial cerebral cortex bilaterally, compatible with hypoxic-ischemic injury (long white arrows), and sparing of the basal ganglia and thalami (short white arrows) and (D) axial FLAIR (fluid attenuated inversion recovery) image from brain MRI done at 12 weeks of age demonstrating severe cystic encephalomalacia bilaterally (arrows). Brain pathology of case 1 (aged 13 months), (E) showing (E1) cross section of brain with reduced white matter volume and ventriculomegaly; (E2) vacuolization of the cerebral cortex, 40X; (E3) pyramidal layer of the hippocampal cornu ammonis showing marked reduction in the number of pyramidal cells and vacuolization, 100X and (E4) hippocampal pyramidal neurons with hypoxia or ischemia (arrows), 200X. (E5–E8) Representative immunofluorescence images from case 1 brain (SARS-CoV-2 positive) showing the presence of nucleus. 4’,6-diamidino-2 phenylindole (DAPI [blue]), spike glycoprotein (green), nucleocapsid protein (red), and colocalization of (merged) nucleocapsid protein and spike glycoprotein around the nucleus as well as in the cytoplasm (arrows), illustrating the presence of virus in the brain.

FIGURE 2

Placental findings in both cases. (A) Histopathology of both placentas demonstrated fetal vascular malperfusion with thrombosis and recanalization of the stem villous vessels (arrow). Inset: higher magnification of thrombosed and recanalized stem villous vessels. Original magnification, 200X, inset 400X (B) chorionic villi with loss of stromal vessels and apoptosis. (C) Representative immunofluorescence images from case placentas (SARS-CoV-2 positive) showing the presence of nucleocapsid protein (red), spike glycoprotein (green), and nucleus (DAPI, blue) with colocalization of (merged) nucleocapsid protein and spike glycoprotein around the nucleus as well as in the cytoplasm (arrows), illustrating the presence of virus (Inset: higher magnification of viral proteins around the nucleus). Paired placental images (left, control placenta with arrowhead and right, case SARS-CoV-2 positive placenta with arrow) showing increased HIF-1α (green, D and E), NLRP1 (red, F and G), MIP-1β (red, H & I), SDF-1 (red, J and K), IL-13 (green, L and M), IL-10 (red, N and O) and reduction in hCG (red, P and Q). (R) Bar graph showing quantification of mean fluorescence intensity of HIF, NLRP, MIF-1 β, SDF-1, IL-13, IL-10 and hCG. Two tailed t test was performed. *P <.05 Control versus CoV (Control = SARS-CoV-2 negative; CoV = SARS-CoV-2 positive). Scale bar = 35 μm for images D through Q.