Sequential bilateral transplantation in Parkinson's disease - Effects of the second graft

Five parkinsonian patients who had received implants of human embryonic mes encephalic tissue unilaterally in the striatum 10-56 months earlier were gr afted with tissue from four to eight donors into the putamen (four patients ) or the putamen plus the caudate nucleus (one patient) on the other side, and were followed for 18-24 months, After 12-18 months, PET showed a mean 8 5% increase in 6-L-[F-18]fluorodopa uptake in the putamen with the second g raft, whereas there was no significant further change in the previously tra nsplanted putamen, Two patients exhibited marked additional improvements af ter their second graft:'on-off' fluctuations virtually disappeared, movemen t speed increased, and L-dopa could be withdrawn in one patient and reduced by 70% in the other, The improvement in one patient was moderate, Two pati ents with atypical features, who responded poorly to the first graft, worse ned following the second transplantation. These findings indicate that sequ ential transplantation in patients does not compromise the survival and fun ction of either the first or the second graft, Moreover, putamen grafts tha t restore fluorodopa uptake to normal levels can give improvements of major therapeutic value.