My understanding is that stem cell transplantation for PD is still in the research stage.
There was a podcast on this topic (approx. 27 mins) about 6 months ago, from the World Parkinson Coalition.
11 New Neurons for Old by World Parkinson Coalition | Free Listening on SoundCloud
There was also a review article on this topic earlier this year.
Are Stem Cell-Based Therapies for Parkinson’s Disease Ready for the Clinic in 2 16? - IOS Press