Immunomodulation and neuroprotection with mesenchymal bone marrow stem cells (MSCs): a proposed treatment for multiple sclerosis and other neuroimmunological/neurodegenerative diseases.

Bone marrow (BM) derived mesenchymal stem cells (MSCs) (non-hematopoietic, stromal cells) can differentiate under certain circumstances into cells from various neuronal and glial type lineages; they also exert immunomodulatory effects. For potential clinical applications, BM-MSCs offer significant practical advantages over other types of stem cells, since they can be obtained from the adult BM (the patient himself being the donor) and can be easily cultured and expanded posing in parallel a very low risk for development of malignancies. We have shown that BM-MSCs cultured with a cocktail of growth factors (containing FGF and BDNF) differentiate into neuronal/glial lineage cells with a predominance of cells expressing astrocytes' markers. BM-MSCs were effective in suppression of chronic EAE in mice and induced neuroprotection, preserving most of the axons in the CNS of successfully-treated animals. Histopathological studies revealed that MSCs could efficiently migrate into the CNS inflamed tissue (both when administered intravenously and intraventricularly) and differentiated into cells expressing neural-glial lineage markers. Our preclinical results indicate that bone marrow can provide a source of stem cells with a potential for migration into inflamed CNS tissue and differentiation into cells expressing neuronal and glial cell markers. Such an approach may provide a feasible and practical way for in situ immunomodulation, neuroprotection and possibly remyelination/regeneration in diseases like multiple sclerosis. We therefore developed a explorative protocol for the evaluation of this therapeutic approach in a small group of patients with MS and other neurodegenerative diseases.