An Ophthalmologist's Insight Into The Viral Pandemics

Ebola Virus Glycoprotein Impairs Human Retinal Pigment Epithelial Barrier Function via the PI3K/Akt-Nrf2 Pathway

Ebola virus (EBOV) causes deadly Ebola virus disease (EVD), and EVD survivors are at high risk of developing blinding ocular complications, which associate with the breakdown of human retinal pigment epithelial (RPE) barrier. Here, we demonstrated EBOV glycoprotein (GP) could directly impair RPE barrier function. EBOV GP significantly decreased expression of tight junction (TJ) proteins in RPE monolayers, resulting in an increase of monolayer permeability. EBOV GP activated PI3K/Akt pathway and induced oxidative stress in RPE cells as evidenced by an increase in the production of reactive oxygen species (ROS), decreased expression of an antioxidant factor, nuclear factor erythroid 2-related factor 2 (Nrf2), and its downstream proteins heme oxygenase 1 (HO-1) and NAD(P)H dehydrogenase (quinone) 1 (NQO1). We found activating Nrf2 could counteract EBOV GP-induced RPE barrier injury. Furthermore, GP2 subunit is the key region in the GP that impairs RPE barrier function. Destruction of RPE barrier function by EBOV GP leads to translocation of bacteria and HIV-1. We confirmed EBOV GP-mediated impairment of RPE barrier function in mice. As an Nrf2 activator, resveratrol displays protective effects on the RPE barrier function. Collectively, our study demonstrates EBOV GP impairs the RPE barrier function through PI3K/Akt-Nrf2 pathway and resveratrol is a promising therapeutic agent for EVD-associated retinal complications.

[Emerging pathogens of ocular infections due to environmental changes-What lies ahead?]

Due to the global effects of climate change numerous infectious diseases are increasingly spreading to regions that were previously hardly or only slightly affected. As ocular involvement is possible in many of these infectious diseases, we must also adapt to new pathogens and clinical pictures in Germany in the medium to long term. Using selected bacterial, viral and mycotic pathogens and diseases as examples, the causes of the increase in dissemination and the consequences for ophthalmology are presented.

Management of COVID-19 in Ophthalmology

From its outbreak in early 2020, the new SARS-CoV-2 infection has deeply affected the entire eye care system for several reasons. Since the beginning of the COVID-19 pandemic, ophthalmologists were among the "high-risk category" for contracting the SARS-CoV-2 infection based on the notion that the eye was suspected to be a site of inoculation, infection, and transmission. Clinical ophthalmologists have been required to learn and promptly recognize the ocular manifestations associated with the COVID-19 disease, with its treatments and vaccinations. Restriction measures, lockdown periods, guidelines to prevent SARS-CoV-2 infection transmission, and the use of telemedicine and artificial intelligence modalities have induced profound modifications. These changes, which are most likely to be irreversible, influence routine clinical practice, education, and research, thus giving rise to a "new ophthalmology in the COVID era". This book chapter aims to provide several notions regarding COVID-19 in ophthalmology, including the SARS-CoV-2 virus infection and transmission modalities; the ocular manifestation associated with the COVID-19 disease; the drugs and vaccines used for COVID-19; the precautions adopted in the ophthalmic practice to limit the spread of the virus; the consequences of the pandemic on the ophthalmic patients, clinicians, and the entire eye care system; and, the future of ophthalmology in the era of "COVID new normal".

Ocular manifestations of recent viral pandemics: A literature review

Viral pandemics often take the world by storm, urging the medical community to prioritize the most evident systemic manifestations, often causing ocular manifestations to go unnoticed. This literature review highlights the ocular complications of the Monkeypox, SARS-CoV-2, MERS, Ebola, H1N1, and Zika viruses as the most recent viral pandemics. Research into the effects of these pandemics began immediately. Moreover, it also discusses the ocular complications of the vaccines and treatments that were used in the scope of the viral pandemics. Additionally, this review discusses the role of the eye as an important route of viral transmission, and thereafter, the International recommendations to reduce the incidence of viral transmission were mentioned. Lastly, this paper wants to lay out a platform for researchers who want to learn more about how viruses show up in the eye.