Potential neuroinvasive and neurotrophic properties of SARS-CoV-2 in pediatric patients: comparison of SARS-CoV-2 with non-segmented RNA viruses

In Vivo confocal microscopy findings after COVID-19 infection

PURPOSE

To evaluate clinical and in vivo confocal microscopy (IVCM) findings of a patient who developed multiple unilateral subepithelial stromal opacities following conjunctivitis that developed during a COVID-19 infection.

METHODS

A 22-year-old female presented to our clinic with blurred right vision. The history revealed that she had experienced a COVID-19 infection one month ago. Redness and stinging of the right eye had started at the same time and she had been prescribed topical antibiotic drops and ointments. The redness in the right eye had decreased but blurred vision had then developed.

RESULTS

Slit lamp examination revealed a normal left eye. Several tiny subepithelial infiltrates without fluorescein staining of the cornea were present in the right eye. The anterior chamber, lens and fundus were bilaterally normal. IVCM revealed irregular corneal epithelial cells with bright borders in addition to scattered inflammatory cells and cell debris in the right eye. There were activated dendritic cells in the subbasal epithelial area with a significant decrease in the subbasal corneal nerve plexus. Clusters of highly reflective cells with an irregular shape were seen in the anterior corneal stroma together with foci of activated keratocytes. The corneal endothelial cell layer was normal. The left eye IVCM findings were all within normal limits. The right eye also showed decreased corneal sensitivity compared to the left.

CONCLUSIONS

The possible role of corneal infiltrates as a trigger for COVID-19 could be explained with an immune-mediated mechanism. SARS-CoV-2 can result in decreased corneal sensitivity through corneal nerve involvement. The clinical results of this effect need to be evaluated in larger series.

HDAC inhibition as neuroprotection in COVID-19 infection

The SARS-CoV-2 virus is responsible of COVID-19 affecting millions of humans around the world. COVID-19 shows diverse clinical symptoms (fever, cough, fatigue, diarrhea, body aches, headaches, anosmia and hyposmia). Approximately 30% of the patients with COVID-19 showed neurological symptoms, these going from mild to severe manifestations including headache, dizziness, impaired consciousness, encephalopathy, anosmia, hypogeusia, hyposmia, psychology and psychiatry among others. The neurotropism of SARS-CoV-2 virus explains its neuroinvasion provoking neurological damage as acute demyelination, neuroinflammation etc. At molecular level, the COVID-19 patients had higher levels of cytokines and chemokines known as cytokines storms which disrupt the blood brain barrier allowing the entrance of monocytes and lymphocytes causing neuroinflammation, neurodegeneration and demyelination. In addition, ischemic, hemorrhagic strokes, seizures and encephalopathy have been observed due to the proinflammatory cytokines. In this sense, to avoid or decrease neurological damage due to SARS-CoV-2 infection, an early neuroprotective management should be adopted. Several approaches can be used; one of them includes the use of HDAC inhibitors (HDACi) due to their neuroprotective effects. Also, the HDACi down regulates the pro-inflammatory cytokines (IL-6 and TNF- decreasing the neurotoxicity. HDACi can also avoid and prevent the entrance of the virus into the Central nervous System (CNS) as well as decrease the virus replication by downregulating the virus receptors. Here we review the mechanisms that could explain how the SARS-CoV-2 virus could reach the CNS, induce the neurological damage and symptoms, as well as the possibility to use HDACi as neuroprotective therapy.