ACE2 expression in the brain during development and susceptibility to brain infection by SARS-COV-2.

The COVID-19 pandemic spread around the world due to the enormous transmission of the SARS-CoV-2 among humans. COVID-19 represents a threat to global public health. The entry of this virus into cells is greatly facilitated by the presence of angiotensin-converting enzyme 2 (ACE2) in the cell membrane. Today we do not have a precise understanding of how this receptor expresses in the brain during human development and, as a consequence, we do not know whether neural cells in the developing brain are susceptible to infection. We review the knowledge about ACE2 expression in the developing human brain, with special attention to the fetal stage. This stage corresponds to the period of the cerebral cortex formation. Therefore, SARS-CoV-2 infection during the fetal period may alter the normal development of the cerebral cortex. Although few cases have been published demonstrating vertical transmission of SARS-CoV-2 infection, the large number of infected young people may represent a problem which requires health surveillance, due to the possibility of cognitive alterations and abnormalities in the development of cortical circuits that may represent a predisposition to mental problems later in life.Copyright © 2023, Instituto de Investigaciones Medicas. All rights reserved.

Considerations on COVID-19 pregnancy: a cases series during outbreak in Bergamo Province, North Italy.

BACKGROUND: COVID-19 has rapidly spread worldwide, with severe complications affecting particularly elderly and compromised subjects. Less information about COVID-19 in pregnancy has been reported so far in the literature. METHODS: Case series on pregnancies complicated by COVID-19. All cases were diagnosed at Bolognini Hospital, Seriate, Italy. These cases are presented to clarify the features of COVID-19 occurring in pregnancy. RESULTS: Four women had symptoms of COVID-19 during pregnancy or immediately after delivery. All cases were confirmed by oropharyngeal swab. All patients presented with fever and low saturation levels at the diagnosis. One case was transferred after diagnosis to a tertiary referral center and delivered the day after for worsening clinical conditions. In the other three cases, bilateral pneumonia was documented at the admission. Antithrombotic therapy was used in most cases. No cases of the infected neonate was reported. At 2 month follow-up, all patients were alive, three were asymptomatic while one presented neurological complication. One more case was described because suspicious for COVID-19, however, it was not confirmed by oropharyngeal swab. CONCLUSIONS: In pregnant women, the peripheral nervous system could be affected. No case of trans-placental passage was reported. The swab could be helpful in diagnosis. The antithrombotic therapy could play a role in the positive course of COVID-19 also in pregnant women.

COVID-19 and vertical transmission: assessing the expression of ACE2/TMPRSS2 in the human fetus and placenta to assess the risk of SARS-CoV-2 infection.

BACKGROUND: Pregnant women have been identified as a potentially at-risk group concerning COVID-19 infection, but little is known regarding the susceptibility of the fetus to infection. Co-expression of ACE2 and TMPRSS2 has been identified as a prerequisite for infection, and expression across different tissues is known to vary between children and adults. However, the expression of these proteins in the fetus is unknown. METHODS: We performed a retrospective analysis of a single cell data repository. The data were then validated at both gene and protein level by performing RT-qPCR and two-colour immunohistochemistry on a library of second-trimester human fetal tissues. FINDINGS: TMPRSS2 is present at both gene and protein level in the predominantly epithelial fetal tissues analysed. ACE2 is present at significant levels only in the fetal intestine and kidney, and is not expressed in the fetal lung. The placenta also does not co-express the two proteins across the second trimester or at term. INTERPRETATION: This dataset indicates that the lungs are unlikely to be a viable route of SARS-CoV2 fetal infection. The fetal kidney, despite presenting both the proteins required for the infection, is anatomically protected from the exposure to the virus. However, the gastrointestinal tract is likely to be susceptible to infection due to its high co-expression of both proteins, as well as its exposure to potentially infected amniotic fluid. TWEETABLE ABSTRACT: This work provides detailed mechanistic insight into the relative protection & vulnerabilities of the fetus & placenta to SARS-CoV-2 infection by scRNAseq & protein expression analysis for ACE2 & TMPRSS2. The findings help to explain the low rate of vertical transmission.

Molecular Pathology Analysis of SARS-CoV-2 in Syncytiotrophoblast and Hofbauer Cells in Placenta from a Pregnant Woman and Fetus with COVID-19.

A small number of neonates delivered to women with SARS-CoV-2 infection have been found to become infected through intrauterine transplacental transmission. These cases are associated with a group of unusual placental pathology abnormalities that include chronic histiocytic intervillositis, syncytiotrophoblast necrosis, and positivity of the syncytiotrophoblast for SARS-CoV-2 antigen or RNA. Hofbauer cells constitute a heterogeneous group of immunologically active macrophages that have been involved in transplacental infections that include such viral agents as Zika virus and human immunodeficiency virus. The role of Hofbauer cells in placental infection with SARS-CoV-2 and maternal-fetal transmission is unknown. This study uses molecular pathology techniques to evaluate the placenta from a neonate infected with SARS-CoV-2 via the transplacental route to determine whether Hofbauer cells have evidence of infection. We found that the placenta had chronic histiocytic intervillositis and syncytiotrophoblast necrosis, with the syncytiotrophoblast demonstrating intense positive staining for SARS-CoV-2. Immunohistochemistry using the macrophage marker CD163, SARS-CoV-2 nucleocapsid protein, and double staining for SARS-CoV-2 with RNAscope and anti-CD163 antibody, revealed that no demonstrable virus could be identified within Hofbauer cells, despite these cells closely approaching the basement membrane zone of the infected trophoblast. Unlike some other viruses, there was no evidence from this transmitting placenta for infection of Hofbauer cells with SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) manifestations during pregnancy in all three trimesters: A case series.

BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic has raised concerns about the susceptibility amongst different groups of the population. Pregnant women are one such group. This study was conducted to investigate the effect of COVID-19 on pregnancy and maternal/neonatal outcomes. CASE PRESENTATION: This case series was conducted on 16 pregnant women with COVID-19 from March 21 to May 11, 2020. Clinical characteristics, pregnancy complications, medication used, maternal/neonatal outcomes, and fatality rate were investigated through this study. The mean age of the patients was 30.06 yrs. Patients from all three trimesters were included (1 in first, 5 in second, and 10 in the third trimesters). The most common clinical symptoms were shortness of breath (n = 10), dry cough (n = 10), myalgia (n = 8), and chills (n = 7). Also, three cases had papulosquamous skin lesions with fissuring. The most common laboratory results were leukocytosis (n = 8), increased liver enzymes (n = 6), elevated CRP (n = 5), and thrombocytopenia (n = 4). There was one case of maternal mortality, five of premature labor pain (PLP), two of preeclampsia, and two of placenta accreta. Twelve pregnancies were terminated (nine cesarean sections, three vaginal deliveries). Among neonates, we had 6 cases of preterm labor. All neonates had negative PCR results. CONCLUSION: Clinical manifestations and paraclinical results were similar to non-pregnant patients. There was no evidence of vertical transmission. PLP and premature rupture of membranes (PROM) were the most common complications in the second and third trimesters of pregnant COVID-19 women, which can lead to rupture of the uterus. Termination and delivery should be planned individually.