Visual Dysfunction in Multiple Sclerosis and its Animal Model, Experimental Autoimmune Encephalomyelitis: a Review

Area of Science:

• Neuroimmunology
• Ophthalmology
• Autoimmune Diseases

Background:

• Visual disabilities are significant symptoms in central nervous system autoimmune diseases like multiple sclerosis (MS).
• Previous research concentrated on neuroinflammation and demyelination within the brain and spinal cord's white matter.
• Neuroinflammatory lesions in the visual pathway of MS patients can impair visual function.

Purpose of the Study:

• To review the direct involvement of the blood-retina barrier (BRB) and blood-brain barrier (BBB) in retinitis and optic neuritis in experimental autoimmune encephalomyelitis (EAE) models.
• To discuss additional inflammatory routes, such as the uvea and cerebrospinal fluid, in EAE-induced visual dysfunction.
• To establish parallels between EAE models and human MS regarding visual pathway inflammation.

Main Methods:

• Review of existing literature on neuroinflammation in MS and EAE models.
• Analysis of neuropathological findings in the retina and optic nerves of chronic EAE animals.
• Examination of the role of BRB and BBB integrity in inflammatory processes affecting the visual system.

Main Results:

• Neuropathological changes, including retinitis and optic neuritis, are observed in the retina and optic nerves of EAE models.
• Despite immunological privilege, inflammation can infiltrate the visual system via the uvea and cerebrospinal fluid.
• Direct breaches or alterations in the BRB and BBB are implicated in EAE-induced visual deficits.

Conclusions:

• The BRB and BBB play critical roles in the pathogenesis of visual disabilities in EAE.
• Inflammation can access the visual system through both direct barrier disruption and alternative pathways.
• Understanding these mechanisms in EAE models provides insights into visual impairment in human MS.