Stem cell treatment is still in the "pre-clinical" stage for almost all diseases. That means people are still trying to see if it works in the lab, or in animal models. There have been a very few studies using fetal dopamine neuroblasts (more developed but still sort of general early-stage cells) but it's not ready for translation to large-scale trials, let alone general medical practice.
So we are very far from having a procedure that would be approved for clinical trials in human beings. There is great potential for the future, but that future - even the first efforts in humans - is still quite a few years down the road. I will paste below an abstract from a recent review article, on parkinsons but the same issues generally apply. (I know the second author and have worked with him although not published together. He's a smart guy and I think does a good job.)
Mov Disord. 2013 Jan;28(1):110-5. doi: 10.1002/mds.25343.
Cell therapy for Parkinson's disease: what next?
Bjorklund A, Kordower JH.
Wallenberg Neuroscience Center, Lund University, Sweden. email@example.com
The idea to use transplants of dopamine-producing cells to substitute for the lost midbrain dopamine neurons in Parkinson's disease (PD) goes back to the 1970s. In this review we give an overview of the history of cell transplantation in animal models of PD, and summarize the experience gained from the open-label and placebo-controlled clinical trials performed so far using intrastriatal transplants of human fetal dopamine neuroblasts. Further development of this therapeutic approach face numerous challenges, for example in the development of protocols that allow generation of fully functional and safe midbrain dopamine neurons from stem cells. Based on recent promising advancements, efforts are now being made to develop standardized and efficient protocols, and adapt these protocols to good laboratory practice (GLP)/good manufacturing practice (GMP) conditions, to move this technology closer to clinical translation.
Copyright © 2013 Movement Disorder Society.