Mesenchymal stem cells in neurological diseases

Author(s): Ibrahim Kassis, Panayiota Petrou, Adi Vaknin-Dembinsky, Dimitrios Karussis

Due to the limited capacity of the CNS for regeneration, more effective treatment of chronic degenerative and inflammatory neurological conditions, but also of acute neuronal damage from injuries or cerebrovascular diseases, could be only achieved, theoretically at least, by stem cells that may have the potential to either regenerate or to support the survival of the existing, partially damaged, cells. A small number of stem cells are found in the adult brain in very specific regions, but this intrinsic stem cell repertoire is rather small and does not contribute significantly to the repair of damaged tissues. Transplantation of stem cells has long been suggested as a possible logical approach for repair of the damaged nervous system. Embryonic cells carrying the pluripotent and self-renewal properties represent the prototype of stem cells, but there are additional somatic stem cells that may be harvested and expanded from various tissues during adult life, such as the mesenchymal stem cells (MSC), which offer several practical advantages for the clinical application. MSC can be obtained from every adult and there are effective culture protocols for their expansion to large numbers for clinical uses. They seem to carry fewer risks for malignancies and some initial indications of their short-term safety (upon system delivery), in clinical settings, exist in the literature. Therefore, in most of the registered clinical trials with stem cells, MSC is the primary stem cell population used. This review summarizes the rationale, the mechanisms and the worldwide clinical experience with MSC, in neurological and other diseases.