Multiple target sites for neural transplantation in Parkinson's disease

Neural transplantation in parkinsonian patients has been performed on an experimental basis for more than a decade. To date, the main transplantation strategy has focused on reinnervating the striatum by the ectopic placement of fetal dopaminergic grafts. Although the clinical results reported in transplanted patients are promising, clinical efficacy has not reached a level to justify the use of neural transplantation as a routine therapeutic procedure for Parkinson's disease. A complete alleviation of all parkinsonian deficits in humans likely depends on the ability to achieve a more complete reinnervation of the basal ganglia dopaminergic circuitry. Consideration of multiple transplant sites to achieve this goal may play a crucial role in optimizing clinical efficacy in parkinsonian patients. In this review we discuss animal studies from our laboratory suggesting that multiple dopaminergic grafts may be a more effective transplantation strategy in Parkinson's disease.