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J Chin Med Assoc ; 84(9): 827-832, 2021 09 01.
Article in English | MEDLINE | ID: covidwho-1320351


The Coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented disruption to the normal operation of the healthcare system. On a worldwide scale, hospitals suspended nonurgent surgeries and outpatient visits to downsize clinical loadings to redistribute manpower to counteract the pandemic's impact. So far, there is no evidence-based guideline defining a clear line between urgent and nonurgent indications of intravitreal injections (IVI). Herein, we aimed to summarize IVI algorithm modifications and discuss the patient prioritization according to medical needs in the hostile environment in the COVID crisis. Assessing current literature, we found that neovascular age-related macular degeneration is considered the utmost priority among conditions that require IVI. Other conditions assigned with a high priority include monocular or quasi-monocular patients (only one eye > 20/40), neovascular glaucoma, and new patients with significant vision loss. Although patients with central retinal vein occlusion and proliferative diabetic retinopathy are not advised to delay treatments, we found no consistent evidence that correlated with a worse outcome. Diabetic macular edema and branch retinal vein occlusion patients undertaking treatment delay should be regularly followed up every 2 to 3 months. Serving as the principle of management behind the algorithm modifications, the reduction of both patient visit and IVI therapy counts should be reckoned together with the risk of permanent visual loss and COVID infection.

COVID-19/epidemiology , Intravitreal Injections/methods , SARS-CoV-2 , Algorithms , Humans , Hygiene , Patient Safety
Int J Mol Sci ; 22(3)2021 Jan 28.
Article in English | MEDLINE | ID: covidwho-1055070


Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.

Angiotensin-Converting Enzyme 2/genetics , COVID-19/genetics , Gene Expression , Induced Pluripotent Stem Cells/cytology , Retina/cytology , SARS-CoV-2/physiology , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Cell Culture Techniques , Cell Line , Humans , Induced Pluripotent Stem Cells/metabolism , Organoids/cytology , Organoids/metabolism , Retina/metabolism , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Virus Internalization