Retinal degeneration in experimental coronavirus retinopathy (ECOR) is associated with increased TNF-alpha, soluble TNFR2 and altered TNF-alpha signaling

How the immune response to the structural proteins of SARS-CoV-2 affects the retinal vascular endothelial cells: an immune thrombotic and/or endotheliopathy process with in silico modeling

Thrombotic events associated with SARS-CoV-2 at the vascular endothelium still remains unclear. The aim of the current study is to determine the relationship between cellular proteins on the (ocular) vascular endothelial surface and the immune thrombotic and/or endotheliopathy process elicited by SARS-CoV-2 using an in-silico modeling. The structural S (spike glycoprotein), N (nucleocapsid protein), M (membrane protein), and E (envelope protein) proteins, an accessory protein (ORF1ab) of SARS-CoV-2 and 158 cellular proteins associated with retinal vascular endothelial cell surface or structure were included in this study for comparison of three-dimensional (3D) structure and sequence. Sixty-nine of the retinal proteins were obtained from the Uniprot database. Remaining proteins not included in the database were included in the study after they were converted into 3D structures using the RaptorX web tool. Sequence and three-dimensional structure of SARS-COV-2 S, N, M, E, ORF1ab proteins and retinal vascular endothelial proteins were compared with mTM-align server. Proteins with significant similarity (score above 0.5) were validated with the TM-align web server. Immune and thrombosis-related protein-receptor interactions of similar proteins was checked with CABS-dock. We detected a high level of structural similarity between E protein and ACE, ACE2, LAT1, and TM9SF4 endothelial proteins. In addition, PECAM-1 was found to be structurally similar to ORF1ab and S protein. When we evaluated the likelihood/potential to stimulate an immune responses/a cytokine release, TLR-2 and TLR-3, which are highly susceptible to SARS-CoV2, showed a potential receptor-protein interaction with retinal vascular endothelial proteins. Our study demonstrates that SARS-CoV-2 proteins may have structural similarities with vascular endothelial proteins, and therefore, as immunological target sites, the counterpart proteins on the endothelial surface of many organs may also be secondarily affected by any immune response against SARS-CoV-2 structural proteins.

COVID Vaccine-Associated Uveitis

PURPOSE

Following the pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2, different vaccines were developed and approved by the main medical authorities under emergency protocol regulations. Although highly effective and well-tolerated in most patients, vaccines can uncommonly cause ocular adverse effects. In this article, the current evidence related to vaccine-associated uveitis is reviewed.

METHODS

A literature review of uveitis post various SARS-CoV-2 vaccinations.

RESULTS

Uveitis was reported following various forms of vaccinations but was more commonly seen following the Pfizer mRNA vaccine which is the most used vaccination worldwide. In western countries, the most common uveitis is mild anterior uveitis, developing within a week of first or subsequent vaccination with good resolution following appropriate topical steroid therapy in most cases. Posterior uveitis and particularly Vogt-Koyanagi-Harada disease was more prevalent in Asia. Uveitis may develop among known uveitis patients and those with other autoimmune diseases.

CONCLUSION

Uveitis following Covid vaccinations is uncommon and has a good prognosis.

Updates on Coronavirus-Related Ocular Manifestations: From the Past to COVID-19 Pandemic

Context: Coronaviruses are the largest RNA viruses associated with some ocular manifestations. There are various contradictory reports about the ocular manifestations of coronaviruses in humans. Different ocular tissues can affect coronavirus-associated infectious diseases. Evidence Acquisition: All manuscripts were collected from PubMed, Google Scholar, and other relevant databases. All searches were done by specific keywords, including "coronavirus," "ocular disease," and "eye." Results: There are various contradictory reports about the ocular effects of coronaviruses in humans. Different ocular tissues are involved in coronavirus-associated infectious diseases. The ductal connection between the upper respiratory tract and eye mucosa through the nasolacrimal duct can be an entrance to respiratory viruses, such as coronaviruses. The coronavirus can infect the retina, conjunctiva, cornea, and uvea of the eye. The primary SARS-CoV-2 receptor, ACE2, is mainly expressed in the posterior tissues of the eye, such as the retina and RPE. Feline CoV, SARS-CoV, MERS-CoV, and infectious bronchitis virus (IBV) are responsible for conjunctiva involvement in coronavirus-related ocular pathogenesis. Also, various studies are held on COVID-19 and the impact of the conjunctiva on diagnosis and medical complications. Given that the cornea has an acceptable expression of ACE2 and TMPRSS2 genes compared to lung tissue, some studies were done on the impact of the cornea in COVID-19. Feline infectious peritonitis virus (FIPV) is also related to uvea complications. The experiments of human and animal models on the effects of coronaviruses on the retina and cornea in the event of various epidemics of coronaviruses and new and unknown ocular complications can be of great help to future studies. Conclusions: Given the importance of investigating the pathogenesis and other routes of SARS-CoV-2 infection, especially in areas other than the respiratory tract, this report attempts to highlight the importance of eye infections caused by the virus, its role in maintaining the virus transmission chain, and its impact on public health.

Increased proinflammatory cytokines in tears correspond with conjunctival SARS-CoV-2 positivity in symptomatic COVID-19 patients

Tear fluid cytokine levels may serve as biomarkers of innate immune system response against SARS-CoV-2 infection. Therefore, our aim was to analyze panel of selected inflammatory cytokines in tears of COVID-19 patients in relation to presence of SARS-CoV-2 viral load in conjunctival secretions. In this study concentrations of TNF-α, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 p70, GM-CSF, and IFN-γ were determined by a magnetic bead assay in tear film collected from 232 symptomatic COVID-19 patients. SARS-CoV-2 ocular infection was confirmed based on positive conjunctival swab-based RT-PCR testing. Viral RNA in conjunctival sac was detected in 21 patients (9%). No relation between presence and the duration of ophthalmic symptoms and SARS-CoV-2 infection detected in conjunctival secretions was found. The tear film concentrations of IFN-γ, TNF-α, IL-5, IL-8 and GM-CSF were found to be significantly greater among patients with positive conjunctival swab results as compared to the group negative for SARS-CoV-2 in conjunctival sac. Our current data depict a group of inflammatory mediators in human tears, which may play a significant role in ocular pathology of SARS-CoV-2 conjunctival infection.

Multiple evanescent white dot syndrome following SARS-CoV-2 infection - A case report

To report a case of MEWDS post-COVID-19 infection with multimodal imaging. A 17-year-old boy reported blurring of vision in both eyes 2 months and 10 days following the SARS-CoV-2 infection. Fundus examination revealed hypopigmented lesions nasal to the optic disc, inferior periphery, and near macula in both eyes. Multimodal imaging was consistent with MEWDS. A complete systemic workup was performed to exclude infectious etiology. Fundus lesions resolved with a course of oral corticosteroids and was confirmed on multimodal imaging.

The role of TNFR2+ Tregs in COVID-19: An overview and a potential therapeutic strategy

COVID-19 is a multi-faceted disease ranging from asymptomatic to severely ill condition that primarily affects the lungs and could advance to other organs as well. It's causing factor, SARS-CoV-2 is recognized to develop robust cell-mediated immunity that responsible to either control or exaggerate the infection. As an important cell subset that control immune responses and are significantly dysregulated in COVID-19, Tregs is proposed to be considered for COVID-19 management. Among its hallmark, TNFR2 is recently recognized to play important role in the function and survival of Tregs. This review gathers available TNFR2 agonists to directly target Tregs as a potential approach to overcome immune dysregulation that affect the severity in COVID-19. Furthermore, this review performs a rigid body docking of TNF-TNFR2 interaction and such interaction with TNFR2 agonist to predict the optimal targeting approach.

Anterior Scleritis Manifesting After Coronavirus Disease 2019: A Report of Two Cases

PURPOSE

The purpose of this study was to report 2 patients with anterior scleritis manifesting after coronavirus disease 2019 (COVID-19).

METHODS

The patients with confirmed COVID-19 developed anterior scleritis after their systemic symptoms were markedly improved. A thorough systemic workup identified no underlying autoimmune diseases. Ocular characteristics and safety and efficacy of systemic immunosuppressive therapy were evaluated.

RESULTS

Case 1 was a 67-year-old woman who presented with necrotizing anterior scleritis in both eyes 3 weeks after the onset of COVID-19. One-week treatment with topical betamethasone and oral prednisolone (65 mg daily) did not result in improvement, so she was started on intravenous cyclophosphamide and subcutaneous adalimumab in addition to oral prednisolone. Necrotizing scleritis was gradually improved over 3 months. Case 2 was a 33-year-old man who presented with sectoral anterior scleritis in his right eye 2 weeks after the onset of COVID-19. He was started on topical betamethasone and oral prednisolone (85 mg daily). One week later, all signs and symptoms disappeared, and topical and oral corticosteroids were gradually tapered off over 2 weeks. There was no recurrence of respiratory symptoms or active scleritis in any cases after discontinuation of treatment.

CONCLUSIONS

These cases suggest that COVID-19 can be associated with anterior scleritis, which responds to immunosuppressive and biologic agents. Ophthalmologists should consider anterior scleritis in patients with COVID-19 who present with ocular pain and redness during the convalescent phase of the illness.

Retinal manifestations in patients with SARS-CoV-2 infection and pathogenetic implications: a systematic review

Introduction

The pandemic of COVID-19 has been caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Apart from respiratory malfunction, COVID-19 causes a system-wide thromboembolic state, leading to serious cardiovascular, cerebrovascular and peripheral vascular manifestations. However, our knowledge regarding retinal manifestations due to systemic COVID-19 is minimal. This systematic review has comprehensively summarized all retinal manifestations secondary to COVID-19 disease recorded till date since the beginning of the pandemic.

Methods

All studies published till November 27, 2020, which have reported retinal manifestations in COVID-19 patients were systematically reviewed using the PRISMA statement.

Results

We included 15 articles: 11 case reports and four cross-sectional case series. The most commonly reported manifestations which did not affect visual acuity were retinal hemorrhages and cotton wool spots. The most common vision threatening manifestation was retinal vein occlusion with associated macular edema. Rarely, patients may also present with retinal arterial occlusions and ocular inflammation. These manifestations may occur from as soon as within a week after the onset of COVID-19 symptoms to more than 6 weeks after.

Conclusion

Mostly causing milder disease, COVID-19 may however lead to severe life-threatening thromboembolic complications, and systemic antithrombotic therapy has been suggested as a prophylactic and therapeutic management strategy for patients affected with serious systemic disease. However, both sick and apparently healthy patients may suffer from various retinal complications which may lead to loss of vision as well. No consensus regarding management of retinal complications with anticoagulants or anti-inflammatory medications have been proposed; however, they may be tackled on individual basis.

The eye: "An organ that must not be forgotten in coronavirus disease 2019 (COVID-2019) pandemic"

The coronavirus family is a group of zoonotic viruses with some recognized reservoirs particularly some bats. A novel coronavirus emerged in the province of Wuhan (China) in December of 2019.The number of infected patient with serious respiratory infection quickly spread around the world to become a global pandemic. The clinical presentation and viral pathogenesis of the coronavirus disease named COVID-19 indicated that the virus is transmitted from person to person through infected droplets entering the respiratory mucosa. Close contact with infected individuals particularly in crowded environments has characterized the rapid spread of the infection. Clinical manifestations of the viral infection have mentioned the presence of some ocular findings such as conjunctival congestion, conjunctivitis and even corneal injury associated with the classical COVID-19 infection. Some animal models of different coronaviruses eye infections have described the viral pathogenesis through tear and conjunctival sampling. On the other hand, we are recommended protective measure to prevent contagion and limit the spread of the virus in health care professionals and contact lenses wearers.

Ocular tropism of coronavirus (CoVs): a comparison of the interaction between the animal-to-human transmitted coronaviruses (SARS-CoV-1, SARS-CoV-2, MERS-CoV, CoV-229E, NL63, OC43, HKU1) and the eye

PURPOSE

Several studies have reported conflicting results on ocular manifestations and transmission of coronavirus disease 2019 (COVID-19) whose causative virus, SARS-CoV-2, belongs to the coronavirus family, the seventh recognized as a human pathogen and the third causing a severe clinical syndrome. COVID-19 primarily affects the lungs, similar to the other human coronaviruses. Comparing the relation between the animal-to-human transmitted coronaviruses (SARS-CoV-1, SARS-Cov-2, MERS-CoV, CoV-229E, NL63, OC43, HKU1) and the eye may contribute to determining their actual eye-tissue tropism and risk of ocular transmission.

METHODS

Literature review was conducted via Pubmed.gov, Google Scholar and medRixv using the following keywords: COVID-19, SARS-CoV-2, SARS-CoV-1, MERS-CoV, CoV-229E, NL63, OC43, HKU1, conjunctivitis, tear swab, ocular expression, ocular symptoms and human angiotensin converting enzyme-2 expression. Studies with lack in methodology were excluded.

RESULTS

Sixteen observational studies were selected. The range for detection of viral RNA in tears was 0-8% for SARS-CoV-1 and 0-5.3% for SARS-CoV-2, while no reports were found for other coronaviruses. Ocular manifestations have been reported for NL63 and SARS-CoV-2. Ocular symptoms in the form of conjunctivitis/conjunctival congestion predominantly were detected in 65 (3.17%) out of 2048 reported patients with COVID-19 (range of 0.8-32%). Eye symptoms were not reported for the other coronaviruses.

CONCLUSIONS

Data aggregation for coronaviruses shows a relatively low eye-tissue tropism. Conjunctival congestion is an uncommon manifestation of COVID-19 similar to all human coronaviruses' infections. In a low percentage of patients, the virus can be excreted in ocular fluids at different stages of the infection, regardless of positive SARS-Cov-2 throat swab. Albeit high viral loads in ocular tissue seem to have relatively low prevalence, the eye should be regarded as a potential source of infection dissemination for COVID-19.

Anterior Acute Uveitis Report in a SARS-CoV-2 Patient Managed with Adjunctive Topical Antiseptic Prophylaxis Preventing 2019-nCoV Spread Through the Ocular Surface Route

PURPOSE

To report the clinical-epidemiological association between acute anterior uveitis and acute bilateral follicular conjunctivitis in a 30-year-old female patient who had tested positive for the SARS-CoV-2 RT-PCR.

METHODS

A 30-year-old female visited emergency ophthalmology care at the Siena Crosslinking Centre, Italy, for a bilateral eye redness lasting two weeks, associated with unilateral photophobia and blurred vision in her right eye. She visited on the 23rd of March 2020 in the full pandemic period and presented chills and fever with a temperature of 39.0°C, associated with complete loss of taste. Since eye examination findings, systemic symptoms and epidemiological criteria correlated with SARS-CoV-2 infection, she was referred to Siena University Hospital, Italy, for the SARS-CoV-2 nasopharyngeal buffer and haematological examinations for uveitis.

RESULTS

Eye examination revealed bilateral conjunctival hyperaemia with acute follicular conjunctivitis associated with right eye acute anterior uveitis characterized by diffuse pigmentary and whitish immune precipitates over the anterior capsule of the crystalline lens and initial anterior lens opacity explaining the blurred vision. Adjunctive prophylactic eye topical treatment, included in the acronym SHYPIO (0.02% sodium hypochlorite solution, 0.6% povidone iodine eye-drops and 10.50% ozonized oil eye-drops), was associated with conventional uveitis therapy to prevent the virus spread through the ocular surface route.

CONCLUSION

Our report demonstrates that complicated acute anterior uveitis (iridocyclitis) with blurred vision could be associated with SARS-CoV-2 infection, being potentially sight-threatening for early complicated lens opacity. Ophthalmologists examining suspected or asymptomatic patients should be aware of the risk of 2019-nCoV infection.

Identification of α-fodrin as an autoantigen in experimental coronavirus retinopathy (ECOR)

The coronavirus, mouse hepatitis virus (MHV), JHM strain induces a biphasic disease in BALB/c mice that consists of an acute retinitis followed by progression to a chronic retinal degeneration with autoimmune reactivity. Retinal degeneration resistant CD-1 mice do not develop either the late phase or autoimmune reactivity. A mouse RPE/choroid DNA expression library was screened using sera from virus infected BALB/c mice. Two clones were identified, villin-2 protein and α-fodrin protein. α-Fodrin protein was used for further analysis and western blot reactivity was seen only in sera from virus infected BALB/c mice. CD4 T cells were shown to specifically react with MHV antigens and with α-fodrin protein. These studies clearly identified both antibody and CD4 T cell reactivities to α-fodrin in sera from virus infected, retinal degenerative susceptible BALB/c mice.

Experimental coronavirus retinopathy (ECOR): retinal degeneration susceptible mice have an augmented interferon and chemokine (CXCL9, CXCL10) response early after virus infection

Mouse hepatitis virus induces a biphasic disease in BALB/c mice that consists of an acute retinitis followed by progression to a chronic retinal degeneration with autoimmune reactivity. Retinal degeneration resistant CD-1 mice do not develop the late phase. What host factors contribute to the distinct responses to the virus are unknown. Herein, we show that IFN-α, IFN-β and IFN-γ act in concert as part of the innate immune response to the retinal infection. At day 2, high serum levels of IFN-γ, CXCL9 and CXCL10, were detected in BALB/c mice. Moreover, elevated levels of CXCL9 and CXCL10 gene expression were detected in retinal tissue. Although IFN-γ and the chemokines were detected in CD-1 mice, they were at significantly lower levels compared to BALB/c mice. These augmented innate responses observed correlated with the development of autoimmune reactivity and retinal degeneration and thus may contribute to the pathogenic processes.

Protein kinase C-zeta mediates retinal degeneration in response to TNF

Tumor necrosis factor-alpha (TNF) has been implicated in retinal ganglion cells (RGC) degeneration in glaucoma. Atypical protein kinase C (PKC) zeta is involved in cell protection against various stresses. The aim of this study was to investigate the potential proapoptotic effects of intravitreal injections of TNF with or without PKCzeta specific inhibitor on the rat retina. TNF was injected in the vitreous of rat eyes alone or in combination with specific PKCzeta inhibitor. PKCzeta and NF-kappaB were studied by immunohistochemistry and western-blotting analysis on retina, and apoptosis quantified by the TUNEL assay. While low basal PKCzeta was observed in the control eyes, TNF induced intense expression of PKCzeta mostly in bipolar cells processes. PKCzeta staining became nuclear when TNF was coinjected with PKCzeta inhibitor. TNF alone did not induce apoptosis in the retina. Coinjection of the PKCzeta-specific inhibitor and TNF, however, induced apoptosis in the inner nuclear and ganglion cell layers. The PKCzeta-specific inhibitor unmasks retinal cells to TNF cytotoxicity showing a link between the proapoptotic effects of TNF and the antiapoptotic PKCzeta signaling pathway.