| Multiple sclerosis (MS) is a neurodegenerative disorder, which results in the death of oligodendrocytes, the myelinating cells of the central nervous system (CNS). Although drug therapies can abate the progression of MS, no treatment has reported significant repair of lost myelin. One possible solution would be to use an embryonic stem cell therapy to derive oligodendrocytes. However, ESC studies have stressed the need for have a homogenous cell population, because ESCs produce teratomas, benign embryonic tumors consisting of all three tissue layers. In this thesis, mouse ESCs were differentiated to oligodendrocytes using a six-step protocol. At each stage of the differentiation protocol, we asked whether teratogenic ESCs persisted within the differentiated cell population. If ESCs persisted, the cell population would have the ability to generate embryoid bodies (EBs). It was found that at each stage of differentiation, we were able to generate EB-like bodies. However, the frequency of EB formation decreased as differentiation progressed indicating a progressive reduction in the number of ESCs. The differentiated cell populations were characterized by immunocytochemistry and RT-PCR and compared and contrasted to starting ESC populations. We conclude that undifferentiated ESCs remain within the heterogeneous population of cells. Therefore, a possible cell therapy must have all ESCs removed from the final differentiated cell population. |
