Eye's Cornea Helps Resist Infection from Coronavirus

Eye's cornea can resist the infection from the novel coronavirus, said researchers. The SARS-CoV-2, the virus that causes COVID-19, does not appear to replicate in the human cornea.

Eye's cornea can resist the infection from the novel coronavirus, said researchers at Washington University School of Medicine in St. Louis. The findings of the study are published in the journal Cell Reports.

The SARS-CoV-2, the virus that causes COVID-19, does not appear to replicate in the human cornea.

Coronavirus
Coronaviruses infect animals, humans, and birds. Human coronaviruses, such as SARS, MERS, and 2019-nCoV cause respiratory distress and even death. The S protein is the infectious agent of the virus.

‘The new study suggests that novel coronavirus does not seem to be able to penetrate the cornea.’

The researchers are yet to explore whether the cornea's associated tissues, namely tear ducts and conjunctiva, are vulnerable to the virus.

Miner, an assistant professor of medicine, of molecular microbiology and of pathology and immunology, teamed up with ophthalmologist Rajendra S. Apte, MD, PhD, to study mouse and human corneas exposed to the herpes simplex, Zika and SARS-CoV-2 viruses.

"Our findings do not prove that all corneas are resistant," said first author Jonathan J. Miner, MD, PhD. "But every donor cornea we tested was resistant to the novel coronavirus. It's still possible a subset of people may have corneas that support growth of the virus, but none of the corneas we studied supported growth of SARS-CoV-2."

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Some COVID-19 patients get eye symptoms such as pink eyes, but researchers are unsure whether the virus causes it, but the cornea and conjunctiva have receptors for the novel coronavirus.

In the new study, researchers wanted to know whether the cornea might serve as an entry point for SARS-CoV-2.

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The researchers tested that by exposing the eye tissue to the different viruses and observing whether they could grow in and replicate. They discovered vital substances in corneal tissue that help promote or inhibit viral growth.

Interferon lambda is one such inhibitor that has been discovered. It prevented the efficient growth of Zika virus and herpes simplex virus in the cornea.

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But with SARS-CoV-2, levels of the interferon substance had no effect on whether the virus could replicate. The study suggested that COVID-19 probably cannot be transmitted through a cornea transplant or similar procedures in the eye.

"It's important to respect what this virus is capable of and take appropriate precautions," he said. "We may learn that eye coverings are not necessary to protect against infection in the general community, but our studies really are just the beginning. We need larger clinical studies to help us better understand all the potential routes of SARS-CoV-2 transmission, including the eye."

Source-Medindia