Placenta protects itself and foetus from coronavirus infection
Researchers can now better explain how the placenta protects itself and the foetus within from the SARS-CoV-2 virus that causes COVID-19. The placenta appears to “shed” a surface protein that the virus uses to break into and infect healthy cells, thereby keeping itself from deadly infection.
In a study of 24 American women who gave birth between July 2020 and April 2021, those afflicted with COVID-19 were found to have high levels of an enzyme called ADAM17 whilst in their third trimester of pregnancy. ADAM17 facilitates the removal of a surface protein (ACE2) on placental cells which the virus uses to gain entry.
According to Dr. Elizabeth Taglauer, assistant professor of paediatrics, Boston Medical Center, US, the placenta may be sensing the maternal COVID-19 infection “and possibly putting in place this mechanism to help shed off ACE2, prevent SARS-CoV-2 from invading the placenta and passing on to the foetus.”
Dr. Taglauer added that earlier studies have shown placental cells become infected in only about 7% to 20% of pregnancies, when the mother contracts COVID-19; however, the virus rarely reaches the foetus. Her research team have planned to study potential “protection pathways” that keeps the virus out of placental cells and foetal blood vessels.
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