Enhancement of the response to levodopa therapy after intrastriatal transplantation of autologous sympathetic neurons in patients with Parkinson disease

Object. There is growing evidence to indicate that tissue transplantation c an potentially be a restorative neurosurgical treatment for patients with P arkinson disease (PD). In this study the authors investigated the clinical effect of unilateral intrastriatal grafting of autologous sympathetic neuro ns in patients with PD. Methods. Four patients with PD who had been observed for I year after graft placement of autologous sympathetic neurons were selected for an analysis of the effect of that procedure. Sympathetic ganglion tissue was endoscopic ally excised from the thoracic sympathetic trunk and grafted into the unila teral caudate head and putamen of the PD patients. No changes were made in the patients' preoperative regimens of antiparkinsonian medications, and cl inical evaluations were made principally according to those established by the Core Assessment Program for Intracerebral Transplantation Committee. Whereas the sympathetic neuron grafts failed to affect clinical scores refl ecting the patients' motor performance, which was evaluated during either t he "on" or "off" phases, the grafts significantly increased the duration of the levodopa-induced on period with consequent reduction in the percentage of time spent in the off phase. This beneficial effect may be explained by the results of the present in vitro experiment, which show that human symp athetic neurons have the ability to convert exogenous levodopa to dopamine and to store this synthesized dopamine. Conclusions. Sympathetic neuron autografts were found to improve performanc e status in patients with PD by reducing the time spent in the off phase. T his clearly indicates that sympathetic ganglion tissue, the use of which in volves few ethical issues, can be an efficacious donor source in cell trans plantation therapy for PD, Further studies are needed to determine whether the grafts may provide long-lasting clinical benefits.