Parkinson's disease (PD) is a common and ultimately incapacitating disease with no cure. The main pathological hallmark of PD is a progressive loss of substantia nigra dopaminergic neurons in the midbrain. The availability of human embryonic stem cells (hESCs) and methods for in vitro differentiation of dopaminergic neurons from hESCs [1–4], animal models of PD, and previous encouraging results from fetal transplants have raised the possibility that one may be able to manufacture human dopaminergic neurons from hESCs in unlimited quantities in vitro. Indeed, we and others have provided evidence for a scalable good manufacture practice (GMP) process that will allow one to obtain dopaminergic neurons from multiple hESC lines [5].
