Letter to the Editor: Immunohistochemical Study of SARS-CoV-2 Viral Entry Factors in the Cornea and Ocular Surface

Bhadani, Pushkar; Agarwal, Balmukund; Kalita, Sangeeta; Bhattacharjee, Harsha; Das, Daisy Rani; Mohapatra, Shyam Sundar Das

doi:10.1097/ico.0000000000002792

Cited by 2 publications

(3 citation statements)

References 5 publications

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“…Correspondingly, conjunctival secretions have been shown to contain SARS-CoV-2 RNA, especially in severely ill patients [30,31], and conjunctivitis related to COVID-19 can occur [32]. However, there is ongoing debate as to whether the conjunctiva can therefore act as a route of infection [33,34]. With regard to corneal tissue, this same question also warrants discussion since it will affect donation practice [35].…”

Section: Discussionmentioning

confidence: 99%

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

et al. 2022

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Concerns of possible transmission of SARS-CoV-2 from donors to patients by corneal transplantation have caused a decline in corneal transplantations. Graft culture media are routinely tested for infectious risks, but it is unclear whether this constitutes a viable means to avoid transmitting SARS-CoV-2 via keratoplasty. We found that SARS-CoV-2 RNA was not present in the medium after seven days of organ culture of corneas from donors (n = 4), who were SARS-CoV-2-positive upon tissue procurement. These medium samples showed no presence of viral RNA. To pursue this question under controlled conditions and further exclude the possibility of productive infection in corneal grafts, we inoculated corneoscleral discs from healthy donors (n = 8) with infectious SARS-CoV-2 and performed PCR testing of the culture medium at various time points. After seven days of culture, we also tested for SARS-CoV-2 RNA within the inoculated corneal tissue. The medium from tissue samples inoculated with SARS-CoV-2 showed no increase in viral RNA, which may indicate lack of viral replication in these corneal grafts. SARS-CoV-2-RNA was, however, detected on or in corneal tissue seven days after inoculation. Our data suggest that corneal grafts may not be permissive for replication of SARS-CoV-2 and demonstrates that PCR testing of culture media cannot safely exclude that tissue has been exposed to SARS-CoV-2. It also demonstrates the difficulty to differentiate between virus adherence and virus replication by PCR testing in SARS-CoV-2 exposed tissue.

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Section: Discussionmentioning

confidence: 99%

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

et al. 2022

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“…The potential risk of virus transmission from corneal transplantation has been addressed and discussed in several studies [ 1 , 2 , 4 , 5 , 9 , 10 , 13 , 18 ], and there is evidence available to support the potential risk of transmission, as well as evidence against it. No transmission of SARS-CoV-2 from the donor to the recipient has been documented in transplantation procedures carried out to date [ 2 ].…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, former and recent Center for Disease Control (CDC) and Food and Drug Administration (FDA) guidelines do not assume a transmission of a respiratory virus through tissue transplantation including human cells, tissues, cellular, and tissue-based products supported by recent studies [1][2][3]. Nevertheless, the potential presence of viral entry factors in the cornea suggests that infection of human corneal tissue is at least possible [4,5]. In addition, the documented isolation of SARS-CoV-2 from human tears and conjunctival swabs demands to exercise even further caution [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Absence of detectable SARS-CoV-2 replication in ex vivo cultured cornea and cornea-derived epithelial cells

Bayyoud

Syrigos

Buschinger

et al. 2022

Graefes Arch Clin Exp Ophthalmol

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Purpose To study the possibility of SARS-CoV-2 to infect human corneal cells and tissues under standard corneal culture conditions using explants of COVID-19 donors and primary cornea-derived epithelial cells. Methods Cornea isolated from deceased COVID-19 donors was cultured for 4 weeks, and SARS-CoV-2 replication was monitored by qRT-PCR. Furthermore, primary corneal epithelial cells from healthy donors were cultured ex vivo and infected with SARS-CoV-2 and human cytomegalovirus (HCMV) as a control. Infection status was assessed by western blotting and reporter gene expression using green fluorescent protein–expressing viral strains. ACE2 and TMPRSS2 receptor expression levels in cornea and epithelial cells were assessed by qRT-PCR. Results We did not detect SARS-CoV-2 replication in 10 corneas isolated from deceased COVID-19 patients and cultured for 4 weeks, indicating absence of infection under natural conditions. Furthermore, high-titer SARS-CoV-2 infection of ex vivo cultured cornea-derived epithelial cells did not result in productive virus replication. In contrast, the same cells were highly permissive for HCMV. This phenotype could potentially be explained by low ACE2 and TMPRSS2 transcriptional activity in cornea and cornea-derived epithelial cells. Conclusions Our data suggest that cornea and limbal epithelial cells are refractory to productive SARS-CoV-2 infection. This could be due to the absence of robust receptor expression levels necessary for viral entry. This study adds further evidence to support the very low possibility of transmission of SARS-CoV-2 from an infected corneal transplant donor to a recipient in corneal organ cultures.

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Letter to the Editor: Immunohistochemical Study of SARS-CoV-2 Viral Entry Factors in the Cornea and Ocular Surface

Cited by 2 publications

References 5 publications

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

Absence of detectable SARS-CoV-2 replication in ex vivo cultured cornea and cornea-derived epithelial cells

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