title: Graft-induced dyskinesias in Parkinson's disease: High striatal serotonin/dopamine transporter ratio.
abstract: Graft-induced dyskinesias are a serious complication after neural transplantation in Parkinson's disease. One patient with Parkinson's disease, treated with fetal grafts 14 years ago and deep brain stimulation 6 years ago, showed marked improvement of motor symptoms but continued to suffer from OFF-medication graft-induced dyskinesias. The patient received a series of clinical and imaging assessments. Positron emission tomography and single-photon emission computed tomography 14 years posttransplantation revealed an elevated serotonin/dopamine transporter ratio in the grafted striatum compatible with serotonergic hyperinnervation. Inhibition of serotonin neuron activity by systemic administration of a 5-HT(1A) agonist suppressed graft-induced dyskinesias. Our data provide further evidence that serotonergic neurons mediate graft-induced dyskinesias in Parkinson's disease. Achieving a normal striatal serotonin/dopamine transporter ratio following transplantation of fetal tissue or stem cells should be necessary to avoid the development of graft-induced dyskinesias.
authors: Centre for Neuroscience, Division of Experimental Medicine, Faculty of Medicine, Hammersmith Hospital, Imperial College London, London, United Kingdom. marios.politis@imperial.ac.uk
authors: Marios
authors: M
authors: Politis
authors: Wolfgang H
authors: WH
authors: Oertel
authors: Kit
authors: K
authors: Wu
authors: Niall P
authors: NP
authors: Quinn
authors: Oliver
authors: O
authors: Pogarell
authors: David J
authors: DJ
authors: Brooks
authors: Anders
authors: A
authors: Bjorklund
authors: Olle
authors: O
authors: Lindvall
authors: Paola
authors: P
authors: Piccini