Treatment of Parkinson’s disease using human stem cells

Abstract

The progressive loss of dopamine neurons (DAn) in the substantia nigra is the main characteristic of Parkinson's disease (PD), the second most common neurodegenerative disorder causing several motor symptoms. Current treatment options for PD are available to help relieve primary motor symptoms, but their long-term effectiveness is limited and they do not stop neuronal degeneration. For this reason, alternative treatment options are being sought in the form of cell replacement therapies (CRT). Several open label clinical trials involving the intrastriatal transplantation of human fetal ventral mesencephalic tissue (hfVM) has provided proof of concept that CRT could be beneficial for some patients, providing relief of motor symptoms. However, the lack of availability of tissue and ethical issues limit the clinical use on a large scale of this strategy, therefore being sought alternative cell sources, based on the use of human stem cells. In this review we provide an overview of the different types of human stem cells currently available, mainly multipotent and pluripotent stem cells, their advantages and disadvantages from an experimental and clinical point of view, and how they are being developed clinically for PD treatment.