Search

Parkinson disease (PD) is a slowly progressive neurodegenerative disease characterized by the loss of dopaminergic neurons and terminals in the nigrostriatal system. Dopamine transporter (DAT) imaging is widely performed for the differential diagnosis of PD and other degenerative parkinsonism from essential tremor, vascular parkinsonism, and drug-induced parkinsonism. DAT is the plasma membrane carrier specific to dopamine neurons that are responsible for re-uptaking dopamine from the synaptic cleft back into the nerve ending. DAT binding might reflect striatal presynaptic dysfunction or DAT expression in PD patients. Longitudinal studies of DAT imaging have reported progressive changes from early PD patients. This imaging may be used as a progressive biomarker. Follow-up DAT imaging for therapeutic interventions has been applied for several anti-parkinsonian drugs. We herein review the progressive changes and therapeutic modification of DAT binding by anti-PD medications in early PD patients.

This study examined whether zonisamide (ZNS) cotreatment delays dopamine transporter (DAT) reduction on SPECT in Parkinson disease (PD) patients. The study participants met the following criteria: (i) age ≥ 40 years; (ii) HY stage = 2 or 3; (iii) average specific binding ratio (SBR) ≥2.00; (iv) levodopa administration without a prior history of ZNS use before the first DAT-SPECT (baseline). Attending physicians initially determined whether ZNS (25 mg/day) should be used or not. Levodopa and other anti-PD medications were not restricted. The second DAT-SPECT (endpoint) was conducted 1.2 ± 0.2 years after the first DAT-SPECT. Clinicoradiological changes of HY stage, UPDRS parts II to IV, dyskinesia subscore, and SBR were calculated. Statistical differences were analyzed by Student's t-test, ANOVA, or multilogistic analysis. ZNS cotreatment improved wearing off and prevented the development of dyskinesia without additional administration of selegiline, entacapone, and dopamine receptor agonists. The endpoint SBR reduced significantly in the non-ZNS group compared to the baseline (P < .01). The SBR decline rate reduced significantly in the ZNS group (P < .01). ZNS was an independent preventive factor for SBR reduction. These results suggested a beneficial potential that ZNS preserves striatal presynaptic DAT expression and slows disease progression in early-stage PD., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective Parkinson's disease (PD) is characterized by the progressive degeneration of the nigrostriatal dopaminergic neurons. Rotigotine is a non-ergot dopamine receptor agonist (DA). Its transdermal patch maintains the effective concentrations for 24 hours. Freezing of gait (FOG) is a common and devastating symptom in PD patients. Little is known about therapeutic effects of rotigotine on FOG in PD patients. Herein we compared how three non-ergot DAs of rotigotine, pramipexole LA and ropinirole CR influence FOG, besides classical motor deficits in PD patients. Methods Rotigotine (maintenance doses of 9-27 mg/day) was administered in 51 patients, 36 patients received pramipexole LA (1.5-4.5 mg/day) and 35 patients received ropinirole CR (8-16 mg/day). The Unified PD Rating Scale (UPDRS) parts I-IV, FOG questionnaire (16 items) and wearing off time were examined from baseline to 7 months after DA administration. UPDRS parts I-IV were evaluated during on time and FOG was recorded during off time if patients experienced wearing off. Results A total of 111 patients completed the study. UPDRS parts II-III scores and wearing off time were significantly reduced after each DA treatment compared to baseline. FOG was found in 54 patients (49%). Most patients developed FOG during off time only. FOG scores were significantly decreased at 2 months after rotigotine treatment whereas pramipexole LA and ropinirole treatment did not alter FOG scores. Conclusion The present study indicates that transdermal patch of rotigotine attenuated the FOG off time. The similar binding affinities to dopamine receptors between rotigotine and dopamine, and 24 hours steady hemodynamics could contribute to the therapeutic mechanism of rotigotine on FOG in PD patients with wearing off.

Yu et al.(1) reported that iron levels in the temporal cortex were reduced in patients with Parkinson disease (PD) compared with age-matched controls. They also determined that patients with Alzheimer disease (AD) had no change in iron levels in the temporal cortex. We would like to know whether Yu et al.(1) included any patients with memory disturbance in this study.

Background: Oxidative stress plays a role in the pathogenesis of neuronal death. Serum levels of urate or lipid were associated with the incidence of Parkinson's disease (PD)., Objective: We compared urate, paraoxonase-1 (PON1), iron, ferritin and lipid in sera of 119 PD patients and 120 healthy controls matched by age, sex and body mass index. We aimed to elucidate whether those serological data are correlated with disease progression., Results: Mean age (SD) of PD patients was 73.4 (8.7) years. Mean Yahr stage (SD) was 3.2 (0.9). Mean disease duration (SD) was 6.9 (5.1) years. Mean dose of L-DOPA (SD) was 355 (157) mg/day. As compared to controls, serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), urate and PON1 activity were significantly reduced, and serum ferritin levels were significantly increased in male and female PD patients. Serum urate levels and PON1 activities were inversely related, and serum ferritin levels were correlated with Yahr stage and PD duration in men and women. Serum levels of TC and LDL-C were inversely related to Yahr stage or PD duration in female patients., Conclusions: Our studies indicated serological profiles of urate, PON1, ferritin, TC and LDL-C in PD patients. These serological changes were linked to PD progression. Metabolism of lipid, oxidant- and antioxidant-related substances may contribute to the pathogenesis and the progression of PD., (Copyright © 2011 S. Karger AG, Basel.)

Long-term therapy with L-3,4-dihydroxyphenylalanine (L-DOPA) in parkinsonian patients is known to lead to dyskinesia within a few years, and repeated administration of L-DOPA is also likely to alter the expression of kappa opioid receptors in the basal ganglia, especially the striatum and substantia nigra pars reticulata, suggesting that kappa opioid receptors might be deeply involved in motor functions. Therefore, effects of TRK-820 ((E)-N-[17-(cyclopropylmethyl)-4,5alpha-epoxy-3,14-dihydroxymorphinan-6beta-yl]-3-(furan-3-yl)-N-methylprop-2-enamide monohydrochloride), a selective kappa opioid receptor agonist, were investigated on rotational behavior in unilateral 6-hydroxydopamine (6-OHDA)-treated rats (hemi-parkinsonian rats) and on L-DOPA-induced dyskinesia produced by administering L-DOPA to hemi-parkinsonian rats for 3 weeks (dyskinesia rats). A single administration of subcutaneous TRK-820 significantly increased spontaneous ipsilateral rotational behavior of hemi-parkinsonian rats at 30 microg/kg though the efficacy was moderate and also significantly inhibited L-DOPA-induced dyskinesia at 10 and 30 microg/kg; this inhibition was reversed in the presence of nor-binaltorphimine, a kappa opioid receptor antagonist. In vivo microdialysis study, TRK-820 (30 microg/kg, s.c.) significantly inhibited L-DOPA-derived extracellular dopamine content in the 6-OHDA-treated striatum in dyskinesia rats, but not in hemi-parkinsonian rats. Moreover, the development of L-DOPA-induced dyskinesia was suppressed by the 3-week co-administration of TRK-820 (3 and 10 microg/kg, s.c.) with L-DOPA. These results have suggested that TRK-820 ameliorates L-DOPA-induced dyskinesia with a moderate anti-parkinsonian effect by inhibiting L-DOPA-induced excessive dopamine release through kappa opioid receptors only in dyskinesia rats; therefore, TRK-820 is expected to become a useful agent for the treatment of L-DOPA-induced dyskinesia.