Abstract:Parkinson’s disease (PD) is a progressive movement disorder common in elderly caused by loss of dopaminergic (DA) neurons in the ventral mesencephalon. Because of its nature of cell degeneration， PD is fairly suitable for cell replacement therapy， using DA neurons or progenitors from various sources， such as differentiation of hESCs. Yet， these hESC-derived progenies should be systematically assessed for safety and efficacy before transplantation into patients. Using MPTP-induced monkey models of Parkinson’s disease， we transplanted hESC-derived DA progenitors into monkey brains for long-term evaluation. We found all monkeys that received cell transplantation exhibited variable but discernible behavioral improvement without tumor formation from graft cell，indicating that hESCs are reliable cell sources for treating neural degenerative diseases such as PDs.