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

Abstract

Pandemic infection secondary to coronavirus disease 2019 (COVID-19) had an important impact on the general population affecting not only respiratory tract but also many other organs. Ocular manifestations are quite common at the level of the anterior segment (conjunctivitis, dry eye), while posterior segment and, in particular, retinal findings are less frequent. In the retina, COVID-19 is associated with vascular events. Since retinal arteries and veins represent an accessible window to the microvasculature of the rest of the body, a better understanding of the profile of retinal vascular occlusive events may help elucidate mechanisms of thrombo-occlusive complications in other organs in patients affected by COVID-19. In this review, we conducted a systematic literature search focused on retinal arterial and/or retinal venous manifestations. Twenty-one studies were included, describing a wide range of manifestations from mild signs like cotton wool spots, focal and flame-shaped hemorrhages, and vein dilation to more severe retinal artery and vein occlusions. Two principal pathogenetic mechanisms are considered responsible for these complications: a hypercoagulative state and a massive inflammatory response leading to a disseminated intravascular coagulation-like syndrome.

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

“…Retrieved genes were combined with the RP-specific differentially expressed genes (see Section 2.4 ) and then used to build the main components of the map. For the disease maps, we chose Parkinson’s disease map ( Fujita et al, 2014 ) and Aging map ( https://progeria.uni.lu ) to explore mechanisms of age-related degeneration, and COVID-19 map used earlier, following reports of potential involvement of COVID-19 in retinal pathology ( Ichhpujani et al, 2022 ; D’Alessandro et al, 2022 ). We emphasize that the choice of these disease maps is for the demonstration purpose only and despite the cited articles this relationship may be stretched.…”

“…Neuroinflammation is an important player upstream of tissue degeneration in RP ( Ortega and Jastrzebska, 2021 ); prominently represented by neuroinflammatory pathways from PD, emphasizing a potential link of PD-related alpha-synuclein to RP ( D’Alessandro et al, 2022 ); kynurenine pathway upstream of prostaglandin synthesis links RP to COVID-19. Other pathways are missing from the map, including autophagy and apoptosis-related mechanisms ( D’Alessandro et al, 2022 ).…”

“…Neuroinflammation is an important player upstream of tissue degeneration in RP ( Ortega and Jastrzebska, 2021 ); prominently represented by neuroinflammatory pathways from PD, emphasizing a potential link of PD-related alpha-synuclein to RP ( D’Alessandro et al, 2022 ); kynurenine pathway upstream of prostaglandin synthesis links RP to COVID-19. Other pathways are missing from the map, including autophagy and apoptosis-related mechanisms ( D’Alessandro et al, 2022 ). This may be caused by a limited scope of the diagram (only 3 disease map fragments and 5 pathways from each source); extending it may broaden the scope and refine the resource further; especially that the list of potential map elements and pathways includes these diagrams.…”

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

“…8 CRVO and other thromboembolic events have been well documented and more frequently reported in relationship with SARS-Cov2 infection. 14–17 Even though, the pathogenesis mechanism remains poorly understood, several potential theories focusing on spike proteins as inducing a systemic inflammation and platelet/endothelial dysfunction are suggested. In fact, viral vaccines provide spike protein information directly through the vector which elicits antibody production, while, the mRNA vaccines provide the nucleoside-modified mRNA encoding the spike protein which elicits both B and T-cell responses in future infections.…”

Editorial: The role of multi-modal imaging in improving refractive cataract surgery and the understanding of retinal disease

“…Although COVID-19 primarily affects the respiratory system, some studies have utilized OCTA imaging technology to demonstrate a varying degrees of retinal vascular abnormalities in the short term ( 9 ). The long-term effects on retinal circulation require further investigation.…”