Neurodegeneration and remyelination in multiple sclerosis

Neuronal and axonal degeneration, as well as inflammation and demyelination, are integral components of the pathology of multiple sclerosis (MS). Neurodegeneration is seen in the earliest stages and throughout the course of the disease and contributes to irreversible physical and cognitive disability. Mitochondrial malfunction and energy failure, loss of trophic support by myelin, ion channel dysfunction, oxidative stress, and excitotoxicity have been identified as possible contributors to neurodegeneration.Remyelination attempts to restore normal axonal function and protects against neuro-axonal loss. Oligodendrocyte progenitor cells are present in the adult brain and under the right conditions, might be able to proliferate, migrate, and differentiate into mature oligodendrocytes, capable of remyelination of MS lesions.In this chapter, we review the underlying pathophysiology of axonal and neuronal injury and the mechanisms of remyelination in MS. A better understanding of these basic principles is required for the development of new therapeutic strategies to prevent disability and restore function in patients.