Authors: Timothy Blenkinsop, PhD, Assistant Professor, Cell, Developmental & Regenerative Biology, and Benjamin tenOever, PhD, Professor, Microbiology, Icahn School of Medicine at Mount Sinai, New York, and other coauthors.
Bottom Line: SARS-CoV-2, the causative agent of COVID-19, is thought to transmit and begin infection in the upper respiratory tract. For this reason, the use of face masks has been recommended for the general public. However, it remains unclear whether infection can also be initiated from the eye, thus requiring additional protective measures.
Results: The new study finds that cells in the eye can be directly infected by SARS-CoV-2, the virus that causes COVID-19.
Why the Research Is Interesting: The findings have an immediate impact on preventive measures to help mitigate the spread of COVID-19 and support new guidance for eye protection that can be instituted worldwide.
Who: Adult human eyes in an in vitro stem cell model.
When: Eyes were exposed to SARS-CoV-2 and studied after 24 hours.
What: The study evaluated whether SARS-CoV-2 could infect both tissues and primary cells in the eye.
How: The donor cells were infected with SARS-CoV-2 and then analyzed through RNA sequencing. The sequences were then mapped to the human genome and compared to non-infected control cells from adult tissues. The expression of the exposed cell where then evaluated. Contracting the virus through the eye could also be corroborated using a small animal model in independent work done Ramus Møller in the tenOever lab.
Study Conclusions: SARS-CoV-2 can infect surface cells of the eye. The exposed cells revealed the presence of infection-associated proteins including ACE2, the virus receptor, and TMPRSS2, an enzyme which allows viral entry. IFNβ, a protein that has antiviral and antibacterial properties, was also found to be suppressed from the exposure to the virus. Additionally, the researchers found that ocular surface cells, particularly the limbus, were susceptible to infection, while the central cornea was less vulnerable.
Said Mount Sinai's Dr. Timothy Blenkinsop of the research: We hope this new data results in additional measures to protect the eyes. We also intend to use these models to test approaches to prevent ocular infections.
Said Mount Sinai's Dr. Benjamin tenOever of the research:
This work was the result of a very productive collaboration from two very different scientific programs. More importantly, the data generated not only adds to our understanding concerning the biology of SARS-CoV-2, but the results also highlight the importance of washing hands, as rubbing one's eyes should now be viewed as an entry point for infection.
Cell Stem Cell