Pathogenesis of Vascular Retinal Manifestations in COVID-19 Patients: A Review

Endothelial ActRIIA inhibition protects the cardiac microvasculature in severe viral respiratory infection

Cardiac complications, including myocardial injury and dysfunction, are common in severe viral respiratory infections (VRI) and are associated with increased mortality 1-3 . The pathophysiology of VRI-induced myocardial injury is multifactorial, but frequently involves structural damage to the heart's microvascular network that leads to subsequent myocardial ischemia and dysfunction 4-6 . Currently, there are no targeted therapies available to prevent or attenuate VRI-associated myocardial injury. Moreover, the molecular mechanisms driving the cardiac microvascular pathology in severe VRI are largely unclear. In this study, we identify increased endothelial cell (EC) activin type IIA receptor (ActRIIA) signaling as a key mediator of cardiac microvascular injury and pathologic remodeling in severe VRI. We show that genetic deletion of EC ActRIIA is sufficient to mitigate EC death and myocardial capillary loss in a murine model of severe influenza infection, which results in improved myocardial perfusion, cardiac function, and survival. We then provide proof-of-concept evidence for two novel pharmacological approaches to target EC ActRIIA pathophysiology in the treatment of VRI-induced cardiac dysfunction.

Acute Hemorrhagic Leukoencephalitis with Concurrent Retinal Vasculitis in an Elderly Japanese Patient

A 68-year-old Japanese man developed a fever, headache, hiccups, and altered consciousness. Brain magnetic resonance imaging revealed a hemorrhagic lesion in the right temporal lobe and multiple high-intensity white matter lesions. A brain biopsy showed pathological findings consistent with acute disseminated encephalomyelitis (ADEM), suggesting a diagnosis of acute hemorrhagic leukoencephalitis (AHLE), an aggressive ADEM variant. The patient also developed myodesopsia and was diagnosed with retinal vasculitis, likely due to a hyperimmune state caused by AHLE. Corticosteroids enabled full recovery. Although AHLE is uncommon in elderly individuals, clinicians should be aware of its occurrence in this patient subgroup and recognize potential retinal manifestations associated with AHLE.

Neovascular Glaucoma as the First Symptom of Bilateral Occlusive Retinal Vasculitis in a 4-Year-Old Girl: A Case Report

Neovascular glaucoma is a rare and serious condition typically associated with advanced ocular or systemic vascular diseases such as central retinal vein occlusion or diabetic retinopathy. This report describes a unique case of neovascular glaucoma presenting for the first time as an initial symptom of bilateral occlusive retinal vasculitis (ORV) in a generally healthy 4-year-old girl. The patient presented with symptoms of pain and redness in the left eye, accompanied by high intraocular pressure. These symptoms were particularly distressing and uncharacteristic for such a young child. Clinical examination revealed significant findings, including elevated intraocular pressure, corneal edema, and iris neovascularization in the left eye. Additional imaging studies, including fluorescein angiography, demonstrated extensive retinal ischemia with peripheral capillary nonperfusion, confirming the diagnosis of occlusive vasculitis. The management of this case was challenging due to the progressive and aggressive nature of the disease in a 4-year-old patient. This article aims to present the diagnostic and therapeutic strategies for the management of this condition. This report highlights a rare case of neovascular glaucoma as the first manifestation of bilateral ORV in a young child. The unusual presentation emphasizes the need for a high index of suspicion and comprehensive evaluation in cases of pediatric neovascular glaucoma. Early diagnosis and prompt, multimodal treatment are crucial in preventing irreversible vision loss in such cases.

Difference in Optical Coherence Tomography Angiography Parameters After SARS-CoV-2 Infection During the Alpha and Delta Variant Dominance Periods

The SARS-CoV-2 infection manifests with diverse clinical manifestations, with severity potentially influenced by the viral variant. COVID-19 has also been shown to impact ocular microcirculation in some patients, but whether this effect varies by viral lineage remains unclear. This prospective study compared clinical features and ocular parameters assessed via optical coherence tomography angiography (OCTA) in patients recovering from SARS-CoV-2 infections during the dominance of two distinctive viral lineages, Alpha (B.1.1.7) and Delta (B.1.617.2), and compared them to a control group. The following parameters were measured: vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CCP) using OCTA, with a manual assessment of the foveal avascular zones in the SCP (FAZs) and DCP (FAZd). A control group was also included. Among 63 patients in the Alpha group and 41 in the Delta group, no eye-related symptoms were reported during the examination. However, the Delta group showed significantly lower VD in the SCP and DCP across all quadrants (p < 0.001-0.039), while the Alpha group showed reduced VD in the foveal CCP (p = 0.005) and significantly wider FAZs and FAZd (p = 0.002 for both). In conclusion, ocular microcirculatory changes differed between the two variants, with Alpha associated with foveal choroidal VD reduction and larger FAZs and Delta linked to lower SCP and DCP VD across multiple regions. These findings highlight the potential for SARS-CoV-2 variants to differentially impact ocular vasculature, underscoring the need for variant-specific follow-up in COVID-19 patients.

The Review of Ophthalmic Symptoms in COVID-19

The COVID-19 pandemic caused by SARS-CoV-2 had a significant impact on the health of the global human population, affecting almost every human organ, including the organ of vision. Research focus on understanding the pathophysiology, identifying symptoms and complications of the disease. Eye-related pathologies are important foci of research due to the potential for direct impact of the virus. Ophthalmologists around the world are reporting various symptoms of eye infections and ocular pathologies associated with SARS-CoV-2. The review of ophthalmic symptoms was conducted to help physicians of various specialties recognize possible ophthalmic manifestations of this viral disease. A literature review was conducted from January 2020 to July 2023 in the PubMed, MEDLINE, Science Direct, Scopus, Scielo and Google Scholar databases. The review of the literature showed that conjunctivitis is the most common ophthalmic symptom observed during the course of COVID-19 and can occur at any stage of the disease. Changes in the eye may result from the direct effect of the virus, immune response, prothrombotic states, comorbidities, and medications used. Symptoms related to the organ of vision can be divided into: changes affecting the protective apparatus of the eye, the anterior eye segment, the posterior eye segment, neuro-ophthalmic, and orbital changes. Ocular symptoms may suggest COVID-19 infection or appear several weeks after recovery. Following COVID-19 vaccinations, a diverse range of ophthalmic symptoms was observed in various locations and at different times, mirroring the ocular symptoms experienced throughout the course of the COVID-19 illness. It is important for physicians of all specialties to be aware of possible potential connections between eye diseases and SARS-CoV-2, in order to effectively diagnose and treat patients.

Bilateral central retinal vein occlusion following COVID-19 vaccination: Cause or coincidence?

AIM

To report a case of sequential bilateral ischemic central retinal vein occlusion (CRVO) following the third dose of anti-COVID 19 vaccination.

METHODS

Observational case report.

RESULTS

A 73-year-old Caucasian male patient, with no known medical history, complained of sudden vision loss in his right eye (RE) 18 days following the third dose of Pfizer-BioNTech anti-COVID 19 vaccination. Ten days later, he suffered from sudden vision loss in his left eye (LE).Best-corrected visual acuity was limited to counting fingers at 50cm in both eyes.Fundus examination of both eyes revealed signs of ischemic central retinal vein occlusion (CRVO) with diffuse superficial and deep retinal hemorrhages in all four quadrants. Diagnosis was confirmed of fluorescein angiography.Optical coherent tomography (OCT) showed an ischemic hyperreflectivity and disorganization of the inner retinal layers in both eyes with significantly increased central macular thickness, associated to intraretinal fluid accumulation in LE.An urgent systemic assessment was requested. A mild hypertension was discovered and the rest of the work up was unremarkable.

CONCLUSION

To our knowledge, we report the first case of bilateral CRVO in a healthy patient after anti-COVID 19 vaccination. CRVO occurred few days following third shot of vaccine followed by a sequential CRVO in the fellow eye in a patient with recently diagnosed very mild hypertension and no thrombo-embolic risk factors, strongly suggesting a relationship between both events. Nowadays, CRVO should be kept in mind as a potential side effect of Covid-19 vaccination and should be added to the spectrum of their ophthalmic complications.

Vascular Alterations Following COVID-19 Infection: A Comprehensive Literature Review

SARS-CoV-2, the causative agent of the ongoing COVID-19 pandemic, has revealed a broader impact beyond the respiratory system, predominantly affecting the vascular system with various adverse manifestations. The infection induces endothelial dysfunction and immune system dysregulation, creating an inflammatory and hypercoagulable state. It affects both microvasculature and macrovasculature, leading to thromboembolic events, cardiovascular manifestations, impaired arterial stiffness, cerebrovascular complications, and nephropathy, as well as retinopathy-frequently observed in cases of severe illness. Evidence suggests that SARS-CoV-2 infection may result in persistent effects on the vascular system, identified as long-term COVID-19. This is characterized by prolonged inflammation, endotheliopathy, and an increased risk of vascular complications. Various imaging modalities, histopathological studies, and diagnostic tools such as video capillaroscopy and magnetic resonance imaging have been employed to visualize vascular alterations. This review aims to comprehensively summarize the evidence concerning short and long-term vascular alterations following COVID-19 infection, investigating their impact on patients' prognosis, and providing an overview of preventive strategies to mitigate associated vascular complications.

COVID-19 and Alzheimer's Disease Share Common Neurological and Ophthalmological Manifestations: A Bidirectional Risk in the Post-Pandemic Future

A growing body of evidence indicates that a neuropathological cross-talk takes place between the coronavirus disease 2019 (COVID-19) -the pandemic severe pneumonia that has had a tremendous impact on the global economy and health since three years after its outbreak in December 2019- and Alzheimer's Disease (AD), the leading cause of dementia among human beings, reaching 139 million by the year 2050. Even though COVID-19 is a primary respiratory disease, its causative agent, the so-called Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), is also endowed with high neuro-invasive potential (Neurocovid). The neurological complications of COVID-19, resulting from the direct viral entry into the Central Nervous System (CNS) and/or indirect systemic inflammation and dysregulated activation of immune response, encompass memory decline and anosmia which are typically associated with AD symptomatology. In addition, patients diagnosed with AD are more vulnerable to SARS-CoV-2 infection and are inclined to more severe clinical outcomes. In the present review, we better elucidate the intimate connection between COVID-19 and AD by summarizing the involved risk factors/targets and the underlying biological mechanisms shared by these two disorders with a particular focus on the Angiotensin-Converting Enzyme 2 (ACE2) receptor, APOlipoprotein E (APOE), aging, neuroinflammation and cellular pathways associated with the Amyloid Precursor Protein (APP)/Amyloid beta (Aβ) and tau neuropathologies. Finally, the involvement of ophthalmological manifestations, including vitreo-retinal abnormalities and visual deficits, in both COVID-19 and AD are also discussed. Understanding the common physiopathological aspects linking COVID-19 and AD will pave the way to novel management and diagnostic/therapeutic approaches to cope with them in the post-pandemic future.

Visualization of automatically combined disease maps and pathway diagrams for rare diseases

Introduction: Investigation of molecular mechanisms of human disorders, especially rare diseases, require exploration of various knowledge repositories for building precise hypotheses and complex data interpretation. Recently, increasingly more resources offer diagrammatic representation of such mechanisms, including disease-dedicated schematics in pathway databases and disease maps. However, collection of knowledge across them is challenging, especially for research projects with limited manpower. Methods: In this article we present an automated workflow for construction of maps of molecular mechanisms for rare diseases. The workflow requires a standardized definition of a disease using Orphanet or HPO identifiers to collect relevant genes and variants, and to assemble a functional, visual repository of related mechanisms, including data overlays. The diagrams composing the final map are unified to a common systems biology format from CellDesigner SBML, GPML and SBML+layout+render. The constructed resource contains disease-relevant genes and variants as data overlays for immediate visual exploration, including embedded genetic variant browser and protein structure viewer. Results: We demonstrate the functionality of our workflow on two examples of rare diseases: Kawasaki disease and retinitis pigmentosa. Two maps are constructed based on their corresponding identifiers. Moreover, for the retinitis pigmentosa use-case, we include a list of differentially expressed genes to demonstrate how to tailor the workflow using omics datasets. Discussion: In summary, our work allows for an ad-hoc construction of molecular diagrams combined from different sources, preserving their layout and graphical style, but integrating them into a single resource. This allows to reduce time consuming tasks of prototyping of a molecular disease map, enabling visual exploration, hypothesis building, data visualization and further refinement. The code of the workflow is open and accessible at https://gitlab.lcsb.uni.lu/minerva/automap/.