The Role of Sex Hormones in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelination disorder with an immune-mediated pathophysiology that affects the central nervous system (CNS). Like other autoimmune conditions, it has a predilection for female gender. This suggests a gender bias and a possible hormonal association. Inflammation and demyelination are hallmarks of MS. Oligodendrocytes are the myelinating cells of the CNS and these continue to be generated by oligodendrocyte precursor cells (OPCs). The process of remyelination represents a major form of plasticity in the developing adult CNS. Remyelination does occur in MS, but the process is largely inadequate and/or incomplete. Current treatment strategies primarily focus on reducing inflammation or immunosuppression, but there is a need for more extensive research on re-myelination as a possible mechanism of treatment. Previous studies have shown that pregnancy leads to an increase in OPC proliferation, oligodendrocyte generation and the number of myelinated axons in the maternal CNS. Studies have also suggested that this remyelination is possibly mediated by estriol. Sex hormones in particular have been shown to have an immuno-protective effect in TH1-driven autoimmunity diseases. The aim of our article is to review the available research on sex hormone-specific immune modulatory effects, assess its remyelination potential in MS, and suggest a future path for more extensive research on sex hormone as a target for therapeutics in MS.