Cell transplantation in Parkinson's disease: problems and perspectives.

In this review article, the authors discuss recent experiments conducted using embryonic tissue and stem cell transplants in experimental models of Parkinson’s disease. The outcomes of clinical transplantation trials is highly variable in terms of motor recovery, and transplants may worsen levodopa-induced motor fluctuations. The risk factors that might predispose to graft-induced dyskinesias are discussed. The authors also introduce Transeuro, a new European Union-funded multicenter consortium which plans to perform transplantation trials, and outline progress made in the use of human embryonic stem cells as a possible source for the generation of dopaminergic neurons, focusing specifically on the field of induced pluripotency. They conclude by introducing the novel method of direct programming which involves the conversion of fibroblasts to neurons without inducing a pluripotent state.