[Neuronal transplantation in animal models of Parkinson disease: in vivo voltammetry, tissue cryopreservation and immunology].

Neuronal transplantation of dopaminergic embryonic ventral mesencephalic cells aims at replacing the lost striatal dopamine in Parkinson's disease. Functional effects of intrastriatal ventral mesencephalic transplants are reflected in improvements of bradykinesia and rigidity. However, a more widespread clinical application critically depends on further technical refinements, specifically in the area of improved survival of the grafted ventral mesencephalic dopamine neurones. This review highlights some of the progress made in the field of ventral mesencephalic transplantation in animal models of Parkinson's disease and also discusses issues and results obtained by our own research group in Munich. Thus we studied whether cryo- or neuroprotective additives during cryopreservation of ventral mesencephalic tissue can improve survival of such tissue/cells following transplantation. Concerning immunological aspects we studied the effects of pooled or co-transplanted embryonic tissue on survival and function of grafts and whether immunosuppression with cyclosporine A has beneficial effects. Possible neurotoxic effects of cyclosporine A were considered in a separate study. Finally, we established in vivo voltammetry to measure dopamine release from the graft and effects of the grafts on related parts of the dopaminergic system in the living animal. In the clinic we employed guidelines for preoperative patient evaluation and respective tests are described.