Immature neural tissue grafts in Parkinson's disease.

Intracerebral transplantation of immature neural tissue is a promising therapeutical approach that has the potential of restoring damaged neuronal circuitries and reversing functional deficits. The development of the technique as a human application has progressed the furthest in Parkinson's disease (PD), with the demonstration of significant longlasting functional improvements, in combination with evidence of surviving grafted tissue, using a fluorodopa positron emission tomography (PET) scanning technique in a few patients. Although the technique is promising, and the effects observed are significant and of clinical importance for the grafted patients in the best cases so far, there are still incomplete effects and no transplantation treatment is suggested since there are still several technical aspects that might further improve the outcome. The progress of the development in the field is briefly reviewed.