New Scientist article (June 2017) provides a good overview of NTCELL (IMHO)
 

Pig brain cells implanted into brains of people with Parkinson’s | New Scientist

(hat tip to Xenos at HU for the link)

I have been following their progress with bated breath! Did you see the short video on their web site of the woman who was the first patient. She seemed healthy and is doing well. Of course I thought of potential problems with the porcine cells, but then thought of other medical uses of animal products and thought 'why not?'