Sadako Kuno

Brain-derived growth factor and nerve growth factor concentrations are decreased in the substantia nigra in Parkinson's disease.

Using highly sensitive sandwich enzyme-linked immunosorbent assays (ELISA), we measured for the first time the concentrations of brain-derived growth factor (BDNF) in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients. BDNF in the human brain (the order of ng/mg protein) was significantly lower specifically in the nigrostriatal dopamine (DA) regions from parkinsonian patients than in those from control patients. The concentration of nerve growth factor (NGF) was also significantly decreased in the substantia nigra of parkinsonian patients in comparison with that in the controls. Since BDNF and NGF may play important roles in survival and differentiation of neuronal cells, the present data indicate that the lack of neurotrophins, especially BDNF, may be involved in the pathogenesis of PD during progress of neurodegeneration of the nigrostriatal DA neurons.

Caspase activities and tumor necrosis factor receptor R1 (p55) level are elevated in the substantia nigra from Parkinsonian brain

Summary. The activities of caspase-1 and caspase-3 were measured by use of fluoropeptides as substrates for the first time in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients. The activities of caspases in the brain were significantly higher in the substantia nigra from parkinsonian patients than those in the brain from control patients (p < 0.01). However, the activities of caspases in the caudate nucleus, putamen, cerebellum, and frontal cortex showed no significant difference between parkinsonian and control patients. The tumor necrosis factor (TNF) receptor R1 (TNF-R1, p55) level was also elevated in the substantia nigra of the parkinsonian brain in comparison with that of controls (p < 0.05). Since both caspases and TNF-R1 may play important roles in apoptotic cell death through TNF-α-induced signaling pathway, our present data suggest the presence of a proapoptotic environment in the substantia nigra of parkinsonian brain, probably inducing vulnerability of neurons and glias towards a variety of noxious factors.

Randomized, double‐blind study of pramipexole with placebo and bromocriptine in advanced Parkinson's disease

We compared the efficacy and safety of pramipexole (PPX) with placebo in the treatment of advanced Parkinsons disease (PD) as an adjunct to levodopa. A bromocriptine (BR) group was included to enable determination of the noninferiority of PPX relative to BR as the standard treatment.

Glial cell line-derived neurotrophic factor in the substantia nigra from control and parkinsonian brains

Glial cell line-derived neurotrophic factor (GDNF) was measured for the first time in the brain (substantia nigra, caudate nucleus, putamen, cerebellum, and frontal cortex) from control and parkinsonian patients by highly sensitive sandwich enzyme-linked immunosorbent assay. In both groups, the levels of GDNF in the various brain regions were lower (pg/mg protein) than those of brain-derived growth factor (ng/mg order), and were significantly higher in the nigro-striatal dopaminergic regions (substantia nigra, caudate nucleus, putamen) than in the cerebellum and frontal cortex (P < 0.05). However, the content of GDNF in the dopaminergic regions showed no significant difference between parkinsonian and control patients.

Immunohistochemical evaluation of the neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on dopaminergic nigrostriatal neurons of young adult mice using dopamine and tyrosine hydroxylase antibodies

The recovery of dopamine (DA) neurons in young adult mice from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) damage was analyzed at various times after MPTP treatment with DA and tyrosine hydroxylase (TH) immunohistochemistry and also by chemical DA assay. A remarkable discrepancy in the recovery rate of DA and TH reactivities of the nigral neurons was observed: the TH immunoreactivities of both cell bodies in the substantia nigra and terminals in the neostriatum were markedly reduced 4 days after MPTP. However, these reactivities progressively improved and almost fully recovered after 25 days, while the DA immunoreactivities were maximally depleted 10 days after, and the depletion continued even through the 25th day. The alteration of DA levels was correlated with that of DA immunoreactivity. These findings suggest that a major effect of MPTP on the DA neurons of young adult mice is a transient neurotoxicity, and that the TH content improves more promptly than that of DA.

Ropinirole is effective on motor function when used as an adjunct to levodopa in Parkinson's disease: STRONG study

We report the results of a randomized, double‐blind, placebo‐controlled, 16‐week study to evaluate the efficacy and safety of ropinirole, 0.75 to 15.0 mg/day, as an adjunct to levodopa. A total of 243 patients were randomly assigned into placebo or ropinirole groups. The mean (standard deviation) dose of ropinirole at endpoint was 7.12 (2.88) mg/day. The primary endpoint—the mean reduction in the Unified Parkinsons Disease Rating Scale (UPDRS) total motor score—was significantly greater for the ropinirole group than the placebo group (−9.5 vs. −4.5, P = 0.00001). The mean reduction in the UPDRS total activities of daily living (ADL) score was also significantly greater for ropinirole than for placebo (−2.7 vs. −1.0, P = 0.0002). The percentage of patients showing at least a 20% reduction in the percentage of time spent “off” was significantly greater for the ropinirole group than for the placebo group (58.7% vs. 38.6%, P = 0.030). A total of 84.3 and 65.6% of the patients experienced adverse events while receiving ropinirole or placebo, respectively. The results showed that ropinirole was more effective than placebo in improving motor function and ADL when used as an adjunct to levodopa in patients with advanced Parkinsons disease.

Influence of monocyte chemoattractant protein 1 gene polymorphism on age at onset of sporadic Parkinson's disease

We studied polymorphisms in the genes for monocyte chemoattractant protein 1 (MCP‐1) and CC chemokine receptor (CCR)‐2 in 171 Parkinsons disease (PD) patients and 340 controls. Although no associations were found in alleles or genotypes, MCP‐1 −2518A/G genotype affected the age‐at‐onset of PD patients. This effect was also detected in a second PD group, suggesting a possible involvement of MCP‐1 in PD.

Effects of tolcapone, a catechol-O-methyltransferase inhibitor, on motor symptoms and pharmacokinetics of levodopa in patients with Parkinson's disease.

SummaryThe effects of tolcapone, a catechol-O-methyltransferase inhibitor, on the bioavailability and efficacy of levodopa were evaluated in 12 patients with Parkinsons disease (PD), 8 of whom showed signs of daily motor fluctuations (wearing-off phenomenon). Motor disabilities were assessed in 12 patients at 7 time points before and after the chronic administration of tolcapone using the Unified Parkinsons Disease Rating Scale (UPDRS). The UPDRS score was improved at all points of determination. Eight patients with wearing-off phenomenon on levodopa showed symptomatic improvement on the combination. The area under the curve (AUC) for levodopa increased by 34% (p=0.0059) after the administration of tolcapone. The elimination half-life (T1/2) of levodopa was significantly prolonged by 81% (p=0.0001) after the treatment. The AUC of 3-O-methyldopa, a metabolite of levodopa, was decreased by 79% (p=0.0001) and the Cmax (maximum concentration) was also decreased by 80% after the administration (p=0.0001) of tolcapone. The combination of tolcapone and levodopa was well tolerated. Our findings suggest that tolcapone improves the pharmacokinetics of levodopa in plasma and motor symptoms of fluctuating PD patients. It is suggested that tolcapone may be a useful drug adjunct to levodopa in treating patients with PD with wearing-off phenomena.

Nationwide multicenter prospective study on the long-term effects of bromocriptine for Parkinson's disease. Final report of a ten-year follow-up.

A 10-year nationwide multicenter prospective study on the long-term efficacy of bromocriptine for Parkinsons disease is reported. Six patients remained on bromocriptine monotherapy for 10 years, while 22 patients achieved good disease control with bromocriptine plus levodopa (added during the course of the study). In the 6 patients on bromocriptine alone, the disease remained in Hoehn and Yahr stage I or II for 10 years. In the other 22 patients on bromocriptine plus levodopa therapy, disease progression was very slow for 7-8 years. None of the 6 patients remaining on bromocriptine monotherapy experienced adverse reactions like the wearing-off phenomenon, dyskinesia, or the on-off phenomenon. Among the 22 patients who started levodopa therapy during the course of the study, these adverse reactions to levodopa were infrequent (10, 3, and 3 patients, respectively). Thus, early introduction and long continuation of bromocriptine therapy with restricted concomitant use of levodopa may have led to very slow disease progression and the suppression of adverse reactions. Although the patients who could be maintained long-term on bromocriptine monotherapy might represent a population who have very slowly progressive disease, their adequate disease control and the low incidence of adverse reactions in the patients who later started concomitant levodopa suggest that the unwanted effects of levodopa may be reduced by early and sustained treatment with bromocriptine. Introduction of bromocriptine monotherapy at an early stage of Parkinsons disease or with restricted use of additional levodopa therapy to bromocriptine when necessary may be a useful strategy for achieving adequate and sustained disease control.

Differential therapeutic effects of dopamine D1 and D2 agonists in MPTP-induced parkinsonian monkeys: clinical implications.

L-DOPA, the precursor of dopamine, remains most effective in the treatment of patients with Parkinsons disease, but prolonged L-DOPA treatment often produces adverse effects, including dyskinesia and psychosis. Dopamine receptors can be divided into two major subtypes, D1 and D2. Might both subtypes of the dopamine receptor be equally relevant to amelioration of parkinsonian symptoms and responsible for the adverse side effects? To address this question, the effects of D1 or D2 receptor agonists alone and in joint administration were examined in MPTP-induced parkinsonian monkeys. The parkinsonian symptoms, such as tremor, bradykinesia and rigidity, and the adverse side effects, such as hyperactivity and aggressiveness, were evaluated independently using different behavioral criteria. The results showed that antiparkinsonian effects can be exerted either by the D1 agonist (SKF 82958) alone or by the D2 agonist (quinpirole) alone, whereas hyperactivity and aggressiveness manifested by dopamine agonists require coactivation of the D1 and D2 receptors. Thus, the antiparkinsonian effect can be dissociated from the adverse effect by therapeutic strategy. It is implied that imbalances in activation of the D1 and D2 receptors may provide a favorable approach for long-term treatment of parkinsonian patients with dopamine drugs.