Dopaminergic function and dopamine transporter binding assessed with positron emission tomography in Parkinson disease.
BACKGROUND
Measuring progression of Parkinson disease (PD) using positron emission tomography may help demonstrate the efficacy of neuroprotective treatments. To date, (18)F-dopa has been the gold standard to measure presynaptic dopaminergic function in PD, but this tracer might overestimate the rate of neuronal death in PD because its uptake also depends on dopamine turnover rather than exclusively on the density of dopaminergic terminals in the striatum. The latter might be assessed using newly developed ligands of the membrane dopamine transporter.


OBJECTIVE
To compare the striatal uptakes of (18)F-dopa and (76)Br-FE-CBT, a dopamine transporter ligand, in patients with PD.


METHODS
The striatal uptakes of (76)Br-FE-CBT and (18)F-dopa were compared using positron emission tomography in 10 patients with early PD and 8 with advanced PD. Correlation of uptakes with motor performance was investigated.


RESULTS
The reduction in (76)Br-FE-CBT binding to 43% of control values was more severe than the reduction in (18)F-dopa uptake (63% of control values) in the putamen of patients with early PD. No significant difference was found between either tracer's uptake in the putamen of patients with advanced PD. Motor performance was highly correlated to (18)F-dopa uptake, whereas correlation to (76)Br-FE-CBT binding was weak.


CONCLUSIONS
Uptake of (18)F-dopa may be up-regulated in early PD, suggesting a compensatory increase of dopamine synthesis in surviving dopaminergic terminals. Positron emission tomography dopamine transporter ligands and (18)F-dopa give complementary information on the presynaptic status of the nigrostriatal dopaminergic system and might be associated to investigate the efficacy of neuroprotective treatments in PD.
Ribeiro
Maria-Joao
MJ
URA CEA-CNRS 2210, Service Hospitalier Frédéric Joliot, 4, place du Général Leclerc, 91401 Orsay, CEDEX, France.
Vidailhet
Marie
M
Loc'h
Christian
C
Dupel
Corinne
C
Nguyen
Jean Paul
JP
Ponchant
Michel
M
Dollé
Frédéric
F
Peschanski
Marc
M
Hantraye
Philippe
P
Cesaro
Pierre
P
Samson
Yves
Y
Remy
Philippe
P
D000368:Aged; D016022:Case-Control Studies; D003342:Corpus Striatum / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D014055:Tomography, Emission-Computed
D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D004298:Dopamine