Effects of disease modifying therapies on brain and grey matter atrophy in relapsing remitting multiple sclerosis

Progressive brain atrophy is a major feature of multiple sclerosis (MS) pathology and is actually considered a major determinant of the progressive accumulation of physical and cognitive disability in MS patients. Although brain atrophy may have different pathological substrates, several lines of evidence suggest that in disease modifying drug (DMD)-treated MS patients, the higher is the anti-inflammatory effect of the DMD the lower is the progression of brain volume loss, grey matter atrophy and the accumulation of disability. Magnetic resonance imaging (MRI)-based measurements of inflammation (focal white matter and grey matter lesions) and neurodegeneration (decrease in brain volume, cortical and deep grey matter atrophy) are currently included among the primary or secondary end-points of Phase II and III randomized clinical trials (RCT). This review summarizes literature data on the effects of DMDs on either whole brain or grey matter atrophy emerged from RCT and from post-marketing studies. Taken all together, literature data show that DMDs are capable to reduce significantly brain inflammation and, although with different degrees of effectiveness, to slow down global brain and/or grey matter atrophy progression. Moreover, the comparison between early and delayed treatments clearly points out that the most relevant effects on brain and grey matter atrophy are observed when DMDs are initiated in the very early disease phases.