Pathophysiological basis of neuromyelitis optica spectrum disorders: What do we know?

Abstract

Neuromyelitis Optica Spectrum Disorders (NMOSD) is a set of clinical manifestations derived from an inflammatory and demyelinating process of the central nervous system that causes lesions primarily in spinal cord and optic nerves but also in other regions such as brainstem, diencephalon or specific brain areas. Most patients with NMOSD are seropositive for autoantibodies against AQP4, the major water channel of astrocytes, however there is a non-negligible percentage of patients, close to 25%, who are seronegative for these antibodies and in whom the presence of antibodies directed against myelin (anti-MOG) could have a pathogenic role that to date has not been well elucidated. Current scientific evidence has allowed recognize that AQP4-IgG is pathogenic in NMOSD, probably by a mechanism involving complement dependent cellular cytotoxicity, causing leucocyte infiltration, cytokine release and blood-brain barrier disruption, which leads to oligodendrocyte death, myelin loss and neuron death. This article presents an evidence-based review, which emphasizes the main aspects in NMOSD pathogenesis.