Brescia research published in Ebiomedicine – The Lancet
The so-called “vertical transmission”, although rare, occurs through the passage of the virus from circulating maternal cells to the chorionic villi of the placenta.
Positive clinical evolution with rapid recovery of both mother and child.
Brescia, 1 September 2020 – A team of researchers from Brescia coordinated by prof. Fabio Facchetti, Director of the Pathological Anatomy Laboratory of the University of Brescia / Spedali Civili di Brescia, provided for the first time the definitive evidence relating to the possibility, very rare, of the so-called “vertical transmission” of the SARS infection. Cov-2 from mother to fetus via the placenta.
The Virology Department of the Experimental Zooprophylactic Institute of Lombardy and Emilia-Romagna (Dr. Antonio Lavazza), the Obstetrics and Gynecology Clinic of ‘University of Brescia / Spedali Civili of Brescia (Director Prof. Enrico Sartori), IFOM of Milan (Dr. Stefano Casola) and the Oncological Immunology Unit of the University of Palermo (Prof. Claudio Tripodo) collaborated to thes tudy, published on the September issue of EbioMedicine, the prestigious editorail gropu of The Lancet.
The researchers examined the spike protein of the SARS-CoV virus from the placenta of 101 women who gave birth between 7 February and 15 May 2020 at the Spedali Civili in Brescia, of which 15 tested positive for the virus, 34 negative and 52 not. evaluable or for lack of appropriate criteria or for having given birth before the declaration of the pandemic.
The study focused on the placenta of a young woman hospitalized at the 37th week of pregnancy for the onset of fever and other symptoms related to Covid-19 infection. The woman, then tested positive for the virus, gave birth by induced birth to a male infant, who also tested positive 24 hours after birth, developing pneumonia with difficulty in breathing. Through various investigation techniques, the researchers demonstrated the presence of SARS-CoV-2 in different components of the placenta, belonging both to the mother (inflammatory cells in the maternal blood) and to the fetus. In particular, viral spike and nucleocapsid proteins, as well as viral RNA, have been observed in abundance in fetal cells that line the chorionic villus (syncytiotrophoblast) and which are in direct contact with maternal blood. This finding was then confirmed by electron microscopy, which made it possible to identify viral particles even in the endothelial cells of the villus capillaries and – never observed before and definitive proof of vertical transmission – in fetal white blood cells circulating within the capillaries.
“The effects and consequences of Coronavirus on pregnant women and newborns are poorly understood, but the growing report of cases of mothers with Covid-19, whose newborns showed signs of infection early after birth, indicated that the transmission of SARS-Cov-2 from mother to child is a possible event – says prof. Fabio Facchetti – The results of our study demonstrate for the first time that vertical transmission of SARS-CoV-2 infection is possible, albeit rare, and that it occurs through the passage of the virus from maternal circulating cells to the chorionic villi of the placenta . A completely unexpected finding was the finding of a placental inflammatory reaction limited to the maternal side, while, despite the infection, the fetal component (chorionic villus) was spared, a “protective” phenomenon that may have depended on the activation of inflammatory inhibitory molecules observed in various components of the villus itself . It is reasonable to think that the reduced damage of the villi has guaranteed a sufficient nutritional exchange between mother and fetus, limiting the damage to the fetus itself”.
Although it is known that Coronavirus infection mainly affects the lungs and that the inflammatory mechanisms triggered by it are the main causes of organ damage, in the case of the placenta, however, the study observed how the clinical evolution was decidedly positive, with a rapid recovery of both mother and baby.This aspect led the researchers to consider that the inflammatory reaction in the placental tissue may have peculiar characteristics, as in fact emerged from their analyzes.
Title of the article published: “SARS-CoV2 vertical transmission with adverse effects on the newborn revealed through integrated immunohistochemical, electron microscopy and molecular analyzes of Placenta” DOI: https://doi.org/10.1016/j.ebiom.2020.102951