Chapter 44 - Cell Therapy in Parkinson's Disease: Understanding the Challenge

Abstract

For more than 35 years cell therapy for Parkinson's disease (PD) has focused on replacement of lost nigrostriatal dopamine (DA) system function responsible for motor symptoms in PD. In animal models and clinical trials a variety of cell-based therapies have been tested, including cells as DA pumps, fetal DA neurons, and DA neurons derived from stem cells. At present, transplantation of fetal DA neurons continues to represent the “gold standard” cell therapy for PD, yet the entire spectrum of outcomes ranging from enduring benefit to no effect persists for this approach. In this review we (1) address the positive effects of what is possible and lessons learned to forward optimization of the approach, (2) examine the implications of basal ganglia “basics” for cell therapy, and (3) discuss parallels between the history of levodopa and cell transplantation therapy that may be useful to consider in this time of renewed clinical interest.