Therapeutic Administration of Mesenchymal Stem Cells Abrogates the Relapse Phase in Chronic Relapsing-Remitting EAE

Multiple Sclerosis (MS) is a neuroinflammatory and immune-mediated chronic disease of the Central Nervous System which progressively damages the axonal myelin sheath, leading to axonal transmission impairment and to the development of neurological symptoms. Most MS cases are characterized by a relapsing-remitting course, and current therapies rely only on the use of immunomodulating drugs which are, however, unable to reverse disease progression. Among the newly proposed alternative therapies, Mesenchymal Stem Cells (MSCs) are considered suitable for MS treatment due to their capacity to modulate the immune response and to modify the pattern of the released cytokines. So far, encouraging results have been obtained with the administration of MSCs before disease onset, mainly in animal models of acute Experimental Autoimmune Encephalomyelitis (EAE) in which MSCs were able to reduce inflammation, thus ameliorating also the disease’s clinical symptoms. On the contrary, only a very small number of studies have investigated the effect of MSCs on relapsing-remitting models of the disease. Here, we investigated the therapeutic potential of MSC administration, both before and after the disease’s onset, in an animal model of MS represented by Dark Agouti rats affected by chronic Relapsing-Remitting EAE. Our results demonstrated that in chronic Relapsing-Remitting EAE the administration of MSCs after the clinical disease’s appearance is able to completely abrogate the relapsing phase and to strongly reduce spinal cord demyelination. These encouraging results have demonstrated that MSCs can provide a protective and reparative strategy for MS treatment.