Intestinal Decontamination Therapy for Dyskinesia and Motor Fluctuations in Parkinson's Disease.

Parkinson's disease is neurodegenerative disorder with an initial robust response to levodopa. As the disease progresses, patients frequently develop dyskinesia and motor fluctuations, which are sometimes resistant to pharmacological therapy. In recent years, abnormalities in gut microbiota have been identified in these patients with a possible role in motor manifestations. Dysbiosis may reduce levodopa absorption leading to delayed "On" or "no-On" states. Among 84 consecutive patients with PD, we selected 14 with levodopa-induced dyskinesia and motor fluctuations with a Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part IV ≥ 8 points following a trial of pharmacological adjustment 2-3 months prior to study enrollment or adjustments in deep brain stimulation therapy. Patients received treatment with sodium phosphate enema followed by oral rifaximin and polyethylene glycol for 7 and 10 days, respectively. Evaluations between 14 to 21 days after starting treatment showed improvement in MDS-UPDRS-IV (P = 0.001), including duration (P = 0.001) and severity of dyskinesia (P = 0.003); duration of medication "Off"-state (P = 0.004); functional impact of motor fluctuations (P = 0.047) and complexity of motor fluctuations (P = 0.031); no statistical improvement was observed in "Off" dystonia (P = 0.109) and total motor scores (P = 0.430). Marked to moderate improvement in dyskinesia was observed in 57% of cases with blinded evaluation of videos. About 80% of patients perceived moderate to robust improvement at follow-up. A therapeutic strategy aimed at decontamination of intestines showed benefit in motor fluctuations and dyskinesia. Further studies should confirm and clarify the mechanism of improvement observed in these patients.

Adjuvant therapies for Parkinson's disease: critical evaluation of safinamide.

Safinamide (SAF) is a new drug developed for the treatment of Parkinson's disease (PD). It is a benzylamino derivative with multiple mechanisms of action and antiparkinsonian, anticonvulsant, and neuroprotective properties. SAF inhibits monoamine oxidase B and dopamine reuptake and glutamate release, blocks voltage-dependent sodium channels, and modulates calcium channels. Although the antiparkinsonian effect can be ascribed in part to the inhibition of the monoamine oxidase B, which is complete at 50 mg, the enhanced benefit seen at the 100 mg dose is probably due to nondopaminergic mechanisms. SAF will represent an important option for patients with both early and advanced PD. In early PD patients, the addition of SAF to dopamine agonists may be an effective treatment strategy to improve motor function, prolong the use of dopamine agonists, and/or delay the introduction of levodopa. In advanced parkinsonian patients, SAF has been demonstrated to significantly increase on time with no, or nontroublesome dyskinesias. All studies performed have demonstrated its efficacy in benefiting both short-term and long-term quality-of-life outcomes in both early and advanced PD patients. SAF has been investigated in long-term (24 months), double-blind, placebo-controlled studies, where it showed a very good safety profile. SAF has not been studied in de novo PD patients, and its potential positive effect on dyskinesia deserves further dedicated studies.

Amino acid supplementation in l-dopa treated Parkinson's disease patients.

BACKGROUND: The correlation between Parkinson disease and malnutrition is well established, however a protein-restricted diet is usually prescribed because of potentially negative interactions between dietary amino acids and l-dopa pharmacokinetics. This strategy could increase the risk of further nutritional deficits. METHODS: A monocentric, prospective, randomized, double-blind pilot study was performed on two groups of Parkinson-affected, protein-restricted, patients: Intervention (n = 7; amino acid supplementation twice daily) and Placebo (n = 7; placebo supplementation twice daily). At enrolment, after 3- and 6-month supplementation, neurological evaluations (UPDRS III, Hoenh-Yahr scale, l-dopa equivalent dose assessment) were performed and blood sample was collected to define insulin sensitivity (QUICKI index) and oxidative stress (oxidized and reduced glutathione). Repeated measure ANCOVA was applied to define time effect and time × treatment interaction. RESULTS: Participants were comparable at baseline for all assessed parameters. Neurological outcomes and l-dopa requirement were comparable in both group after 6-month of supplementation, without time × treatment interaction. The decrease in insulin sensitivity, as assessed by QUICKI index, observed after 6 months in both groups, was greater in Placebo than in Intervention (time effect p < 0.001; time × treatment interaction p = 0.01). Moreover, despite no changes in total erythrocyte glutathione concentrations, oxidized glutathione levels decreased by 28 ± 17% in the Intervention while increased by 55 ± 38% in Placebo (time effect p = 0.05; time × treatment interaction p = 0.05), after 6-month supplementation. CONCLUSIONS: Amino acid supplementation, assumed with shrewd temporal distribution, did not show detrimental effects on neurological and pharmacological control in protein-restricted Parkinson-affected patients, chronically treated with l-dopa. Furthermore, daily amino acid supplementation partially counteracted insulin resistance development and the loss in antioxidant availability.

Relaxation guided imagery reduces motor fluctuations in Parkinson's disease.

BACKGROUND: Motor fluctuations in Parkinson's disease (PD) cause major disabling symptoms. OBJECTIVE: We aimed to assess the efficacy of relaxation guided imagery in PD patients with motor fluctuation. METHODS: In a prospective pilot, case cohort, PD patients underwent (i) a relaxation session with relaxation guided imagery, and (ii) a control session of relaxing music. Three-day diaries were completed at baseline and after each intervention. Subsequently, patients received discs for home listening-a relaxation guided imagery disc and a relaxing music disc. After three months the patients were interviewed by phone. RESULTS: Twenty one PD patients participated and 19 completed this study. There was a significant increase in the percent of "on" time after listening to the relaxation guided imagery disc as compared with baseline (from 47.7% to 62.8%, 95% CI 5.26-25.03, p = 0.005). Relaxing music caused no significant change in percent of "on" time from baseline (from 47.7% to 53.0%, p = 0.161). Although all sessions were performed in "on" state, there was a significant decrease in UPDRS motor subscores after each of the two sessions as compared with the UPDRS score before the session (relaxation guided imagery mean reduction -3.81 p = 0.0002 and after relaxing music mean reduction -1.95, p = 0.001), significantly more so after the relaxation guided imagery (p = 0.020). After 3 months listening to the relaxation guided imagery disc increased "on" time from baseline by 12.6% (95% CI 3.19-28.39, p = 0.111) but this did not reach statistical significance. CONCLUSION: In this pilot study we showed that relaxation guided imagery is a promising treatment for PD.

Two new adenosine receptor antagonists for the treatment of Parkinson's disease: istradefylline versus tozadenant.

INTRODUCTION: Adenosine A2A receptors are localized in the brain, mainly within the caudate and putamen nuclei of the basal ganglia. Their activation leads to stimulation of the 'indirect' pathway. Conversely, administration of A2A receptor antagonists leads to inhibition of this pathway, which was translated into reduced hypomotility in several animal models of parkinsonism. AREAS COVERED: In this review, the effects of two A2A receptor antagonists, istradefylline and tozadenant, on parkinsonian symptoms in animal and humans will be discussed. EXPERT OPINION: Animal studies have shown potent antiparkinsonian effects for several A2A receptor antagonists, including istradefylline. In clinical trials, istradefylline reduced OFF time when administered with levodopa, but results are inconclusive. Results with tozadenant are scarce. Modification of thalamic blood flow compatible with reduced inhibition was noted in one small trial, followed by a significant reduction in OFF time in a larger one. Therefore, both drugs show promising efficacy for the reduction of OFF time in levodopa-treated Parkinson's disease patients, but further research is needed in order to obtain definitive conclusions.