M18 Spatio-temporal Characterisation Of Human Fetal Neural Stem Cells For Cell Replacement Therapies

Abstract

Human fetal neural stem cells (hfNSC) hold great potential for cell therapy strategies but further studies are still needed for a proper understanding of these cells. In the present work we characterised hfNSC isolated from cortex, whole ganglionic eminence (WGE), cerebellum and forebrain at several developmental stages (6–12 weeks post conception (wpc)). We showed that tissue obtained from younger fetuses survived significantly better than older ones after dissociation, due to the presence of a higher number Nestin positive neural precursors. These results suggested the presence of more differentiated cells in samples obtained from older fetuses. In agreement, an increased expression of mature neuronal markers was observed in samples from older fetal brains. Interestingly, the proliferation ratios were not different between developmental stages. A common feature was observed for all the cultures studied independently of the brain area and the developmental stage; they went through 3–4 initial critical passages characterised by high percentages of cell death and substantial variability in the proliferation ratio. After this critical period, they stabilised, reduced cell death and maintained a constant expansion potential. Forebrain hfNSC were the most readily expandable and cerebellar cells the ones that proliferated least. Finally, we analysed the regional identity and differentiation potential of cortical and WGE derived hfNSC along passages. The expression of mature region specific markers after 3 and 6 passages was down-regulated. Interestingly, cortical cultures acquire a ventral phenotype along passages. Nevertheless, they both keep the multipotency after 6 passages and the potential to differentiate to mature region specific neurons. In conclusion, here we show that hfNSCs can be expanded in vitro and may be suitable for cell therapy in HD.