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No link between striatal dopaminergic axons and dopamine transporter imaging in Parkinson's disease
Author(s) -
Honkanen Emma A.,
Saari Laura,
Orte Katri,
Gardberg Maria,
Noponen Tommi,
Joutsa Juho,
Kaasinen Valtteri
Publication year - 2019
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.27777
Subject(s) - dopamine transporter , putamen , dopaminergic , tyrosine hydroxylase , dopamine , neuroscience , dopamine plasma membrane transport proteins , parkinson's disease , substantia nigra , axon , medicine , endocrinology , chemistry , biology , disease
Background Brain dopamine transporter binding has been considered a possible biomarker for nigrostriatal degeneration in PD. Objective To investigate whether dopamine transporter binding is associated with the number of dopaminergic neurites in the putamen. Methods Tyrosine hydroxylase–positive nerve fibers were counted from postmortem putamen sections taken from 14 parkinsonism patients who had been scanned with dopamine transporter single‐photon emission computed tomography antemortem. Fiber counts were correlated with putamen dopamine transporter binding and SN neuron counts. Results The putamen dopamine transporter specific binding ratio did not correlate with the putamen tyrosine hydroxylase–positive axon counts (r = 0.00; P = 1.0; PD patients: r = 0.07; P = 0.86). The nigra neuron counts had a positive correlation with the putamen tyrosine hydroxylase–positive axon counts. Conclusions Striatal dopamine transporter imaging does not associate with axonal nor somal loss of the nigrostriatal neurons in PD. It may reflect dopaminergic activity rather than number of surviving neurons or their striatal projection axons. © 2019 International Parkinson and Movement Disorder Society