Status Of Sars-Cov-2 Specific Pro- & Anti-Viral Genes On The Ocular Surface

To investigate the expression of SARS-CoV-2-specific host attachment, entry and anti-viral response genes in the various layer of donor eyes, including the ocular surface.

Cadaver eyes from health controls (n=5), COVID-19 infected (n=5) and COVID-19 recovered (n=2) donors were used for the study. Tissue sections were prepared from the donor eyes for immunofluorescence imaging. Dissection of ocular tissues based on different anatomical regions of the eye also performed was used for RNA extraction. Impression cytology from controls (n=8) and dry eye disease (DED) patients (n=7) obtained during pre-pandemic period was used to for RNA extraction. Expression of ACE2, TMPRSS2, CTSL, type 1, 2 and 3 IFNs (interferons) were assessed by immunofluorescence microscopy and/or quantitative PCR.

Increased expression of ACE2, TMPRSS2, CTSL were higher in ocular surface layers compared to other regions/layers of the eye. Further, increased ocular surface expression of ACE2 and TMPRSS2; along with decreased expression of type 1 IFNs (IFN alpha) was observed in COVID-19 infected eyes compared to healthy controls and COVID-19 recovered eyes. A similar expression pattern was observed on the ocular surface of DED patients compared to controls.

Ocular surface tissue exhibit higher expression of host factors aiding the attachment and entry of SARS-CoV-2. Ocular surface of DED subjects exhibits higher expression of ACE2, CTSL and TMPRSS2. Hence, topical agents that alters such profile would be beneficial in the prophylaxis against ocular manifestation associated with COVID-19.