Exploring Mitochondrial Localization of SARS-CoV-2 RNA by Padlock Assay: A Pilot Study in Human Placenta.

The ongoing COVID-19 pandemic dictated new priorities in biomedicine research. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is a single-stranded positive-sense RNA virus. In this pilot study, we optimized our padlock assay to visualize genomic and subgenomic regions using formalin-fixed paraffin-embedded placental samples obtained from a confirmed case of COVID-19. SARS-CoV-2 RNA was localized in trophoblastic cells. We also checked the presence of the virion by immunolocalization of its glycoprotein spike. In addition, we imaged mitochondria of placental villi keeping in mind that the mitochondrion has been suggested as a potential residence of the SARS-CoV-2 genome. We observed a substantial overlapping of SARS-CoV-2 RNA and mitochondria in trophoblastic cells. This intriguing linkage correlated with an aberrant mitochondrial network. Overall, to the best of our knowledge, this is the first study that provides evidence of colocalization of the SARS-CoV-2 genome and mitochondria in SARS-CoV-2 infected tissue. These findings also support the notion that SARS-CoV-2 infection can reprogram mitochondrial activity in the highly specialized maternal-fetal interface.

Stillbirth and fetal capillary infection by SARS-CoV-2.

We presented the case of stillbirth in a paucisymptomatic mother affected by SARS-CoV-2. At gross examination, the placenta showed a diffuse marble appearance and a focal hemorrhagic area. Multiple areas of hemorrhagic or ischemic necrosis with central and peripheral villous infarctions and thrombosis of several maternal and fetal vessels with luminal fibrin and platelet deposition were observed. All lesions seemed to be synchronous. Virus particles were identified within the cytoplasm of endothelial cells using electron microscopy, whereas SARS-CoV-2 RNA was detected in the placental tissue using real-time reverse transcription-polymerase chain reaction. Here, fetal vascular malperfusion was associated with infection; in fact, electron microscopy images showed that marked SARS-CoV-2 endotheliotropism involved the intravillous fetal capillaries. Furthermore, we confirmed that syncytiotrophoblast is the major target cell type for SARS-CoV-2 infection of the placenta. In conclusion, the possible consequences of the action of the placentotropic SARS-CoV-2 included the occurrence of vertical transmission, as reported in the literature, and/or stillbirth: the latter possibility may be triggered by a hampered maternal and/or fetal perfusion of the placenta. The diffuse thrombosis and subsequent ischemia of fetal capillaries induced by COVID-19 cannot be predicted by standard clinical surveillance.

Does Lung Ultrasound Have a Role in the Clinical Management of Pregnant Women with SARS COV2 Infection?

Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infection is a major health threat. Pregnancy can lead to an increased susceptibility to viral infections. Although chest computed tomography (CT) represents the gold standard for the diagnosis of SARS-CoV-2 pneumonia, lung ultrasound (LUS) could be a valid alternative in pregnancy. The objectives of this prospective study were to assess the role of LUS in the diagnosis of lung involvement and in helping the physicians in the management of affected patients. Thirty pregnant women with SARS-CoV-2 infection were admitted at the obstetrical ward of our Hospital. Mean age was 31.2 years, mean gestational age 33.8 weeks. Several LUS were performed during hospitalization. The management of the patients was decided according to the LUS score and the clinical conditions. Mean gestational age at delivery was at 37.7 weeks, preterm birth was induced in 20% of cases for a worsening of the clinical conditions. No neonatal complications occurred. In 9 cases with a high LUS score, a chest CT was performed after delivery. CT confirmed the results of LUS, showing a significant positive correlation between the two techniques. LUS seems a safe alternative to CT in pregnancy and may help in the management of these patients.