NEURAL STEM CELLS AND TRANSPLANTATION STUDIES IN PARKINSON'S DISEASE

Parkinson's disease (PD), one of the most frequent neurodegenerative disorders, is primarily caused by the selective degeneration of specific neuronal populations, particularly dopaminergic neurons within the substantia nigra projecting to the striatum (nigrostriatal neurons). The current pharmacological treatments are efficient in the early stage of the disease but with the continuous use of the pro-dopaminergic medication may become less effective and cause motor complications. Cell therapy is an emergent alternative therapeutic strategy to PD and consists in the replacement of damaged neurons by new cells that could help to restore the nigrostriatal pathway. For this purpose, stem cells constitute a promising tool that could provide new sources of cells to be used for experimental transplantation studies in PD, as well as in other neurological disorders. Numerous studies are being made with the use of tissue specific neural progenitors obtained from either fetal or adult nervous systems. in this chapter we will summarize the numerous preclinical and clinical studies performed so far in animal models of the disease as well as in patients and how the use of neural stem cells might improve the current cell therapies.