Monoamine transporter availability in Parkinson's disease patients with or without depression.
OBJECTIVE
Depression is a common symptom in patients suffering from Parkinson's disease (PD) and markedly reduces their quality of life. As post-mortem studies have shown, its presence may reflect extensive cell loss in the midbrain and brainstem with imbalances in monoaminergic neurotransmitters. However, in vivo evidence of specific monoaminergic deficits in depressed PD patients is still sparse. Therefore, we studied PD patients with depression (PD+D) and without depression (PD-D) using high-resolution single-photon emission computed tomography (SPECT) and the monoamine transporter marker [(123)I]FP-CIT.


METHODS
A magnetic resonance imaging-based region-of-interest analysis was applied to quantify the specific-to-nondisplaceable [(123)I]FP-CIT binding coefficient V(3)'' in the striatum, thalamus and midbrain/brainstem regions.


RESULTS
PD+D patients had significantly lower V(3)'' compared with PD-D patients in the striatum (p<0.001), thalamus (p=0.002), and midbrain/brainstem (p=0.025). Only PD+D patients without selective serotonin reuptake inhibitor (SSRI) treatment showed lower thalamic and midbrain V(3)'' than controls (p<0.001, p=0.029). In a small sub-group of SSRI-treated PD+D patients neither thalamic V(3)'' nor midbrain/brainstem V(3)'' differed from those in PD-D patients (p=0.168, p=0.201) or controls (p=0.384, p=0.318).


CONCLUSIONS
Our data indicate that depression in PD is associated with a more pronounced loss of striatal dopamine transporter availability that is most likely secondary to increased dopaminergic degeneration. In addition, depressed PD patients have a lower availability of midbrain/brainstem monoamine transporters than nondepressed PD patients. These findings provide in vivo evidence in support of the known post-mortem data demonstrating more extensive nerve cell loss in PD with depression and indicate that SPECT imaging can help to identify pathophysiological changes underlying nonmotor symptoms in this common movement disorder.
Hesse
Swen
S
Department of Nuclear Medicine, University of Leipzig, Stephanstrasse 11, 04103 Leipzig, Germany. Swen.Hesse@medizin.uni-leipzig.de
Meyer
Philipp M
PM
Strecker
Karl
K
Barthel
Henryk
H
Wegner
Florian
F
Oehlwein
Christian
C
Isaias
Ioannis Ugo
IU
Schwarz
Johannes
J
Sabri
Osama
O
D000368:Aged; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D003863:Depression / Q000150:complications* / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000378:metabolism*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
D015306:Biogenic Monoamines; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D050486:Serotonin Plasma Membrane Transport Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane