SARS-CoV-2 can infect and propagate in human placenta explants

Area of Science:

• Virology
• Obstetrics
• Immunology

Background:

• The SARS-CoV-2 pandemic has been linked to adverse maternal and neonatal outcomes.
• Placental pathology has been observed in pregnant individuals with SARS-CoV-2 infection.
• Understanding viral interactions at the maternal-fetal interface is crucial.

Purpose of the Study:

• To investigate the susceptibility of human placental tissue to SARS-CoV-2 infection.
• To characterize viral replication and cellular localization within the placenta.
• To assess the host response to SARS-CoV-2 infection in placental precision-cut slices (PCSs).

Main Methods:

• Human placental precision-cut slices (PCSs) were exposed to SARS-CoV-2.
• Viral replication was assessed by measuring infectious virus release.
• Detection of viral proteins and RNA was performed using immunohistochemistry and in situ hybridization.
• Host gene expression, including cytokine and interferon responses, was analyzed.

Main Results:

• SARS-CoV-2 successfully replicated within placental PCSs, releasing infectious virions.
• Viral presence was confirmed in syncytiotrophoblasts, cytotrophoblasts, villous stroma, and Hofbauer cells.
• SARS-CoV-2 infection did not induce significant cytotoxicity or pro-inflammatory cytokine release.
• A significant upregulation of interferon type III transcripts was observed.

Conclusions:

• Human placental tissue is susceptible to SARS-CoV-2 infection and supports viral propagation.
• The findings highlight the potential for SARS-CoV-2 to infect the maternal-fetal interface.
• Further research is warranted to understand the implications of placental SARS-CoV-2 infection.