Stem cell transplantation in multiple sclerosis: current status and future prospects.

This article provides an overview of the current knowledge relating to the potential use of transplanted stem cells in the treatment of patients with multiple sclerosis (MS). Two types of stem cells, CNS-derived neural stem/precursor cells (NPCs) and bone marrow-derived mesenchymal stem cells (MSCs) are considered to provide reproducible and robust therapeutic effects when intravenously or intrathecally injected into both rodents and primates with experimental autoimmune encephalomyelitis. Furthermore, preliminary safety data concerning the use of intrathecally injected autologous MSCs in patients with progressive MS are available. We discuss how the data gathered to date challenge the narrow view that the therapeutic effects of NPCs and MSCs observed in the treatment of MS are accomplished solely by cell replacement. Both types of stem cell, when transplanted systemically, might instead influence disease outcome by releasing a plethora of factors that are immunomodulatory or neuroprotective, thereby directly or indirectly influencing the regenerative properties of intrinsic CNS stem/precursor cells.