Neural transplantation has emerged as a possible therapy for Parkinson's disease (PD).
Clinical studies performed during the 1990s, where dopaminergic neurons derived from the
human embryonic brain were transplanted into striatum of patients with PD, provided proof-
of-principle that long-lasting therapeutic benefits can be achieved. Subsequent studies, in
particular two that followed a double-blind, sham surgery, placebo-control design, showed
variable and mostly negative results. They also revealed that some patients develop …