Stem Cell Research at Johns Hopkins Medicine: Parkinsons Disease

Ted Dawson, M.D., Ph.D., professor of neurology and co-director of NeuroICE explains where we are in using stem cells to treat Parkinsons Disease.

Were creating induced pluripotent stem (iPS) cells from patients with Parkinsons disease with the intent of turning them into dopamine neurons that we can study in a dish and also put into animals. We want to see if human iPS derived neurons grown in culture or in a mouse can lead to disease, and if it can, to study the mechanisms of why cells degenerate and test our hypotheses, drugs and targets in human cells.

If you look at the work thats been done in neurodegenerative diseases in animal models, weve been good at slowing progression of disease, but when we go to humans, the trials fail. So why is that? Perhaps because in mice were able to intervene very early in the disease, but in humans were treating late. Maybe the treatment would work if we treated early in humans, but this would require the ability to diagnosis the disease prior to the onset of symptoms. The other possibility is that Parkinsons disease in a mouse is different than a man.

Using iPS cells we can test new therapies in human neurons for the first time. One of the reasons there have been tremendous new therapies with cancers is that scientists can biopsy human tumors and use those cells to design drugs. Now stem cells are putting us in a position to be able to study neurodegenerative diseases in a similar way.

For developmental diseases such as Down syndrome and schizophrenia, theres no question in my mind that iPS will change the ways those diseases are studied and treated. With an adult-onset neurodegenerative disorder that takes 50 years to develop in humans, the big question is whether an iPS cell will have Parkinsons disease after growing in a mouse for a few months. We just dont know. But we need to do the experiment.

Lots of people thought Parkinsons was going to be low hanging fruit for stem cell transplantation. But we still dont fully understand the transplantation process and how to optimize it. There needs to be a lot of work done to get to that point. And medical therapy for Parkinsons is so advanced that transplantation right now probably isnt going to be any better than what we can already do. But that doesnt mean we shouldnt be forging ahead, using stem cells to discover more about the disease in order to find new drugs as well as refine our ideas about transplantation.

--Interviewed by Maryalice Yakutchik

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Stem Cell Research at Johns Hopkins Medicine: Parkinsons Disease