Role of Neutrophils on the Ocular Surface.

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.

Organic Photo-antimicrobials: Principles, Molecule Design, and Applications.

The emergence of multi-drug-resistant pathogens threatens the healthcare systems world-wide. Recent advances in phototherapy (PT) approaches mediated by photo-antimicrobials (PAMs) provide new opportunities for the current serious antibiotic resistance. During the PT treatment, reactive oxygen species or heat produced by PAMs would react with the cell membrane, consequently leaking cytoplasm components and effectively eradicating different pathogens like bacteria, fungi, viruses, and even parasites. This Perspective will concentrate on the development of different organic photo-antimicrobials (OPAMs) and their application as practical therapeutic agents into therapy for local infections, wound dressings, and removal of biofilms from medical devices. We also discuss how to design highly efficient OPAMs by modifying the chemical structure or conjugating with a targeting component. Moreover, this Perspective provides a discussion of the general challenges and direction for OPAMs and what further needs to be done. It is hoped that through this overview, OPAMs can prosper and will be more widely used for microbial infections in the future, especially at a time when the global COVID-19 epidemic is getting more serious.

Integrins: An Important Link between Angiogenesis, Inflammation and Eye Diseases.

Integrins belong to a group of cell adhesion molecules (CAMs) which is a large group of membrane-bound proteins. They are responsible for cell attachment to the extracellular matrix (ECM) and signal transduction from the ECM to the cells. Integrins take part in many other biological activities, such as extravasation, cell-to-cell adhesion, migration, cytokine activation and release, and act as receptors for some viruses, including severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). They play a pivotal role in cell proliferation, migration, apoptosis, tissue repair and are involved in the processes that are crucial to infection, inflammation and angiogenesis. Integrins have an important part in normal development and tissue homeostasis, and also in the development of pathological processes in the eye. This review presents the available evidence from human and animal research into integrin structure, classification, function and their role in inflammation, infection and angiogenesis in ocular diseases. Integrin receptors and ligands are clinically interesting and may be promising as new therapeutic targets in the treatment of some eye disorders.

In the eye of the storm: SARS-CoV-2 infection and replication at the ocular surface?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first emerged in December 2019 and spread quickly causing the coronavirus disease 2019 (COVID-19) pandemic. Recent single cell RNA-Seq analyses have shown the presence of SARS-CoV-2 entry factors in the human corneal, limbal, and conjunctival superficial epithelium, leading to suggestions that the human ocular surface may serve as an additional entry gateway and infection hub for SARS-CoV-2. In this article, we review the ocular clinical presentations of COVID-19 and the features of the ocular surface that may underline the overall low ocular SARS-CoV-2 infection. We critically evaluate the studies performed in nonhuman primates, ex vivo organ culture ocular models, stem cell derived eye organoids and the differences in infection efficiency observed in different parts of human ocular surface epithelium. Finally, we highlight the additional work that needs to be carried out to understand the immune response of the ocular surface to SARS-CoV-2 infection, which can be translated into prophylactic treatments that may be applied to other organ systems.

Eyes on coronavirus.

Recently, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has spread around the world and is receiving worldwide attention. Approximately 20% of infected patients are suffering from severe disease of multiple systems and in danger of death, while the ocular complications of SARS-CoV-2-infected patients have not been reported generally. Herein, we focus on two major receptors of SARS-CoV-2, ACE2 and CD147 (BSG), in human ocular cells, and interpret the potential roles of coronaviruses in human ocular tissues and diseases.

More than loss of taste and smell: burning watering eyes in coronavirus disease 2019.

OBJECTIVES: To evaluate ocular symptoms in European non-hospitalized patients with severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and to investigate associations with the demographic data as well as nasal and general physical symptoms. METHODS: In this prospective, observational study, 108 non-hospitalized patients with PCR-confirmed SARS-CoV-2 infection not requiring intensive care were asked about disease-associated ocular symptoms, demographic data, as well as general physical and nasal symptoms using a standardized questionnaire. Total ocular symptom score (TOSS) was evaluated during and, retrospectively, before development of coronavirus disease 2019 (COVID-19). Associations between TOSS and demographic data as well as general and nasal symptoms were evaluated. RESULTS: Seventy-five of the 108 COVID-19 patients (69.4%) had at least one ocular symptom during COVID-19. The most common symptoms included burning sensations in 39 (36.1%), epiphora in 37 (34.3%) and redness in 28 (25.9%), compatible with conjunctivitis. These symptoms occurred 1.96 ± 3.17 days after the beginning of COVID-19 and were mild. TOSS was significantly higher during COVID-19 (1.27 ± 1.85) than before the infection (0.33 ± 1.04; p < 0.001). There were no significant associations between TOSS and gender (ß coefficient -0.108; p 0.302), age (-0.024; p 0.816), rhinorrhoea (-0.127; p 0.353), nasal itching (-0.026; p 0.803), sneezing (0.099; p 0.470), nasal congestion (-0.012; p 0.930), cough (-0.079; p 0.450), headache (0.102; p 0.325), sore throat (0.208; p 0.052), or fever (0.094; p 0.361). CONCLUSIONS: Ocular involvement in European non-hospitalized individuals with COVID-19 seems to be highly underestimated. Overall, these ocular symptoms, including burning sensations, epiphora and redness, seem to be mild and to not need treatment.

The implication of ocular manifestation of COVID-19 for medical staff and patients - systematic review.

INTRODUCTION: SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) is a coronavirus that causes COVID-19 (coronavirus disease 2019) with mild to severe respiratory illness. It is a highly contagious disease transmitted through direct or indirect contact with infected people or contaminated surfaces, mainly through respiratory droplets, but other routes are being investigated. OBJECTIVE: It is known that coronaviruses (CoVs) can cause a variety of ocular pathologies in animals, including conjunctivitis, anterior uveitis, retinitis, and optic neuritis, many of which are severe. However, there is no evidence of the SARS-CoV-2 presence in the eye tissue of asymptomatic patients, even if the symptomatic incidence is low. This systematic review presents updated literature on this issue. ABBREVIATED DESCRIPTION OF THE STATE OF KNOWLEDGE: COVID-19 has now spread throughout the continents and poses a global threat to public health. The risk of rapidly overloading health care systems and causing substantial mortality worldwide is real. On 11 March 2020, the World Health Organization (WHO) announced coronavirus as a global pandemic. Several studies described a few cases with initial ocular symptoms followed by systemic symptoms of the disease. SUMMARY: Although the frequency of transmission of SARS-CoV-2 infection through the eye is low, ocular symptoms are not uncommon in COVID-19. In some cases, eye symptoms may be the first signs of illness. This implies the need for hygienic recommendations and use of personal protective equipment (PPE) for medical staff and other services to minimize COVID-19 infection of both health-care workers and patients. A triage for ophthalmic outpatient clinic is mandatory.