Higher dopamine transporter density in Parkinson's disease patients with depression.
BACKGROUND
Depression is a frequent non-motor symptom in Parkinson's disease (PD) with increasing rates with the progression of the disease. Molecular imaging studies have shown a reduction of dopamine transporter (DAT) density in depressed PD patients (dPD); however, DAT role in the pathophysiology of PD depression is not clear since clinical matching was inappropriate and DAT reduction could be attributed to PD severity.


OBJECTIVE
To further examine the role of DAT in PD depression, this study compared thoroughly matched depressed vs. non-depressed PD patients (ndPD).


METHODS
Twenty PD patients (n = 10 ndPD; n = 10 dPD) matched for age and disease severity were submitted to brain SPECT imaging with [(99m)Tc]-TRODAT-1, a DAT radioligand. DAT-binding potential was calculated using regions of interest bilaterally drawn in the striatum, caudate, and putamen. Depression was defined according to Beck Depression Inventory (BDI; cut-off >18).


RESULTS
Mean BDI scores were higher in dPD (25.0 +/- 5.6) than in ndPD patients (8.0 +/- 1.9, p < 0.0001). DAT density was greater on dPD especially in the left caudate (dPD 0.87 +/- 0.19 vs. ndDP 0.69 +/- 0.18, p = 0.02) and right putamen (dPD 0.37 +/- 0.07 vs. ndPD 0.28 +/- 0.13, p = 0.03) than in ndPD patients.


CONCLUSIONS
Our results suggest that in vivo DAT density is increased in dPD patients as compared to ndPD, suggesting that DAT is implicated in the pathophysiology of PD depression.
Felicio
Andre C
AC
Instituto Israelita de Ensino e Pesquisa (IIEP), Hospital Israelita Albert Einstein (HIAE), Francisco Morato ave, 4293, Postal Code 05521-000, Sao Paulo, Brazil. cf.andre@gmail.com
Moriyama
Tais S
TS
Godeiro-Junior
Clecio
C
Shih
Ming C
MC
Hoexter
Marcelo Q
MQ
Borges
Vanderci
V
Silva
Sonia M A
SM
Amaro-Junior
Edson
E
Andrade
Luiz A F
LA
Ferraz
Henrique B
HB
Bressan
Rodrigo A
RA
D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D003863:Depression / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D015259:Dopamine Agents / Q000494:pharmacology / Q000627:therapeutic use; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy; D011485:Protein Binding / Q000187:drug effects; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D018709:Statistics, Nonparametric; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes / Q000493:pharmacokinetics
D015259:Dopamine Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; D007980:Levodopa