Nonmotor Fluctuations in Parkinson's Disease

Phantosmia in Parkinson's Disease: A Systematic Review of the Phenomenology of Olfactory Hallucinations

Olfactory dysfunction is a prevalent non-motor symptom in Parkinson's disease (PD), affecting approximately 65-90% of subjects. PD patients may also report odor perception in the absence of any external source, often referred to as olfactory hallucinations (OHs) or phantosmia. This study aims to explore the current understanding of OHs in PD and offer a comprehensive overview of their prevalence and characteristics. We conducted a systematic search of the literature published on PubMed from inception to July 2023 regarding OHs in PD, following PRISMA guidelines. From the 2875 studies identified through database searching, 29 studies fulfilled the necessary criteria and underwent data extraction. The frequency of OHs in PD patients varies widely, ranging from 0.5% to 18.2%, with female prevalence ranging from 36% to 75% of the patients. Olfactory experiences may vary widely, ranging from pleasant scents to unpleasant odors. Several studies have indicated the concurrent presence of other types of hallucinations alongside phantosmia, especially visual and auditory hallucinations. OHs in PD are a type of hallucination that has been largely overlooked. To gain a deeper understanding of OHs in PD patients, the next crucial step should involve the development and validation of a dedicated questionnaire.

Fluctuations in Parkinson's disease and personalized medicine: bridging the gap with the neuropsychiatric fluctuation scale

Background

Neuropsychiatric fluctuations (NpsyF) are frequent and disabling in people with Parkinson's disease (PD). In OFF-medication, NpsyF entail minus neuropsychiatric symptoms (NPS) like anxiety, apathy, sadness, and fatigue. In ON-medication, NpsyF consist in plus NPS, such as high mood, hypomania, and hyperactivity. Accurate identification of these NpsyF is essential to optimize the overall PD management. Due to lack of punctual scales, the neuropsychiatric fluctuation scale (NFS) has been recently designed to assess NpsyF in real time. The NFS comprises 20 items with two subscores for plus and minus NPS, and a total score.

Objective

To evaluate the psychometric properties of the NFS in PD.

Methods

PD patients with motor fluctuations and healthy controls (HC) were assessed. In PD patients, the NFS was administrated in both the ON-and OFF-medication conditions, together with the movement disorders society-unified Parkinson disease rating scale parts I-IV. Depression (Beck depression scale II), apathy (Starkstein apathy scale) and non-motor fluctuations items of the Ardouin scale of behaviour in PD (ASBPD OFF and ON items) were also assessed. NFS internal structure was evaluated with principal component analysis consistency (PCA) in both medication conditions in PD patients and before emotional induction in HC. NFS internal consistency was assessed using Cronbach's alpha coefficient. NFS convergent and divergent validity was measured through correlations with BDI-II, Starktein, and ASBPD OFF and ON non motor items. Specificity was assessed comparing NFS global score between the HC and PD populations. Sensitivity was evaluated with t-student test comparing the ON-and the OFF-medication conditions for NFS global score and for minus and plus subscores.

Results

In total, 101 consecutive PD patients and 181 HC were included. In PD patients and HC, PCA highlighted one component that explained 32-35 and 42% of the variance, respectively. Internal consistency was good for both the NFS-plus (alpha =0.88) and NFS-minus items (alpha =0.8). The NFS showed a good specifity for PD (p < 0.0001) and a good sensitivity to the medication condition (p < 0.0001).

Conclusion

The satisfactory properties of the NFS support its use to assess acute neuropsychiatric fluctuations in PD patients, adding to available tools.

Oscillatory beta dynamics inform biomarker-driven treatment optimization for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons and dysregulation of the basal ganglia. Cardinal motor symptoms include bradykinesia, rigidity, and tremor. Deep brain stimulation (DBS) of select subcortical nuclei is standard of care for medication-refractory PD. Conventional open-loop DBS delivers continuous stimulation with fixed parameters that do not account for a patient's dynamic activity state or medication cycle. In comparison, closed-loop DBS, or adaptive DBS (aDBS), adjusts stimulation based on biomarker feedback that correlates with clinical state. Recent work has identified several neurophysiological biomarkers in local field potential recordings from PD patients, the most promising of which are 1) elevated beta (∼13-30 Hz) power in the subthalamic nucleus (STN), 2) increased beta synchrony throughout basal ganglia-thalamocortical circuits, notably observed as coupling between the STN beta phase and cortical broadband gamma (∼50-200 Hz) amplitude, and 3) prolonged beta bursts in the STN and cortex. In this review, we highlight relevant frequency and time domain features of STN beta measured in PD patients and summarize how spectral beta power, oscillatory beta synchrony, phase-amplitude coupling, and temporal beta bursting inform PD pathology, neurosurgical targeting, and DBS therapy. We then review how STN beta dynamics inform predictive, biomarker-driven aDBS approaches for optimizing PD treatment. We therefore provide clinically useful and actionable insight that can be applied toward aDBS implementation for PD.

Characteristics of fatigue in Parkinson’s disease: A longitudinal cohort study

Objective

To assess the prevalence, evolution, clinical characteristics, correlates and predictors of fatigue as well as to investigate the influence of comorbid fatigue on the longitudinal changes in motor and non-motor symptoms over a 2-year longitudinal follow-up period in a large cohort of patients with Parkinson’s disease (PD).

Materials and methods

A total of 2,100 PD patients were enrolled from the Parkinson’s Disease &amp; Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC), and their motor and non-motor symptoms were assessed biennially using comprehensive scales, including the 16-item Parkinson Fatigue Scale (PFS-16). Each PD patient was categorized as PD with or without fatigue on the basis of a cut-off mean PFS-16 score of 3.3.

Results

The prevalence of fatigue in our cohort was 36.8%. Compared to PD patients without fatigue, PD patients with fatigue were more likely to be older, have a longer disease duration, and higher baseline levodopa equivalent daily dose (all p &lt; 0.05). Moreover, PD patients with fatigue showed more severe motor and non-motor phenotypes than those without fatigue. Overall, high total Unified Parkinson’s Disease Rating Scale (UPDRS) score (odds ratio [OR] = 1.016, 95% confidence interval [CI]: 1.009–1.024), Non-Motor Symptoms Scale score (OR = 1.022, 95% CI: 1.015–1.029), postural instability and gait difficulty (PIGD) subtype (OR = 1.586, 95% CI: 1.211–2.079), presence of excessive daytime sleepiness (EDS; OR = 1.343, 95% CI: 1.083–1.666), and wearing-off (OR = 1.282, 95% CI: 1.023–1.607) were significantly associated with fatigue in PD patients (all p &lt; 0.05). High total UPDRS score at baseline (OR = 1.014, 95% CI: 1.002–1.027, p = 0.028) increased the risk of developing fatigue during follow-up. Although significant, the odds ratios were low and confidence intervals were narrow. Analysis of disease progression showed significant group differences in motor and non-motor symptoms. In comparison with the never-fatigue group, the persistent-fatigue group showed significantly greater progression in motor, autonomic dysfunction, sleep, depression and cognitive symptoms (all p &lt; 0.05).

Conclusion

Increased disease severity, presence of the PIGD subtype, EDS, and wearing-off were associated with fatigue in PD patients. Significant subgroup-level differences were observed in the progression of motor and non-motor symptoms across different fatigue subgroups of PD patients.

Off-time Treatment Options for Parkinson's Disease

Motor fluctuations (MF) are deemed by patients with Parkinson's disease (PD) as the most troublesome disease feature resulting from the increasing impairment in responsiveness to dopaminergic drug treatments. MF are characterized by the loss of a stable response to levodopa over the nychthemeron with the reappearance of motor (and non-motor) parkinsonian clinical signs at various moments during the day and night. They normally appear after a few years of levodopa treatment and with a variable, though overall increasing severity, over the disease course. The armamentarium of first-line treatment options has widened in the last decade with new once-a-daily compounds, including a catechol O-methyltransferase inhibitor - Opicapone-, two MAO-B inhibitors plus channel blocker - Zonisamide and Safinamide and one amantadine extended-release formulation - ADS5012. In addition to apomorphine injection or oral levodopa dispersible tablets, which have been available for a long time, new on-demand therapies such as apomorphine sublingual or levodopa inhaled formulations have recently shown efficacy as rescue therapies for Off-time treatment. When the management of MF becomes difficult in spite of oral/on-demand options, more complex therapies should be considered, including surgical, i.e. deep brain stimulation, or device-aided therapies with pump systems delivering continuous subcutaneous or intestinal levodopa or subcutaneous apomorphine formulation. Older and less commonly used ablative techniques (radiofrequency pallidotomy) may also be effective while there is still scarce data regarding Off-time reduction using a new lesional approach, i.e. magnetic resonance-guided focused ultrasound. The choice between the different advanced therapies options is a shared decision that should consider physician opinion on contraindication/main target symptom, patients' preference, caregiver's availability together with public health systems and socio-economic environment. The choice of the right/first add-on treatment is still a matter of debate as well as the proper time for an advanced therapy to be considered. In this narrative review, we discuss all the above cited aspects of MF in patients with PD, including their phenomenology, management, by means of pharmacological and advanced therapies, on-going clinical trials and future research and treatment perspectives.

HLDF-6 peptides exhibit neuroprotective effects in the experimental model of preclinical Parkinson's disease

The mechanisms of the neuroprotective action of the hexapeptides HLDF-6 encoded by the amino acid sequence 41-46 of Human Leukemia Differentiation Factor and its homoserine derivative HLDF-6H were studied in an experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced model of Parkinson's disease (PD). C57Bl/6 mice received two intraperitoneal injections of 18 mg/kg MPTP-HCl, with an interval of 2 hours. MPTP-induced motor dysfunction was assessed using horizontal grid test. Our data show that chronic intranasal administration of peptides (3 weeks, 300 μg/kg/day) restored normal levels of dopamine and improved its turnover rates in the striatum. Furthermore, peptide administration increased serum estradiol levels and led to a significant improvement in motor functions in MPTP-treated mice. Additionally, peptide treatment increased the levels of mRNA encoding neurotrophin BDNF, but normalized the levels of mRNA encoding the inflammatory mediators TGFβ1, IL1β and IFNγ in the brain. Collectively, our behavioral and biochemical studies demonstrate that HLDF-6 peptides have a therapeutic potential for treating PD. We propose that HLDF-6 peptides may exert their neuroprotective mechanism, at least in part, by normalizing estradiol levels and modulating the expression of key factors involved in neurotrophic support and neuroinflammation.

Anti-Parkinson's Disease Activity of Sanghuangprous vaninii Extracts in the MPTP-Induced Zebrafish Model

Parkinson's disease (PD) is a devastating disease of the central nervous system that occurs mainly in the elderly age group, affecting their quality of life. The PD pathogenesis is not yet fully understood and lacks the disease-modifying treatment strategies. Sanghuangprous vaninii (S. vaninii) is a perennial fungus with a plethora of pharmacological activities including anti-cancer and antioxidant activity and so on. However, no study till date has reported its neuroprotective effect against symptoms that are similar to PD in pre-clinical investigation. In the current study, we investigated anti-PD-like effects of S. vaninii mycelium extracts (SvMEs) on MPTP-induced PD in zebrafish. We observed that the loss of dopaminergic neurons and neurovascular reduction were reversed by using SvMEs in the zebrafish brain in a concentration-independent manner. Moreover, it also relieved locomotor impairments in MPTP-induced PD zebrafish. In addition, SvMEs exerted significant antioxidant activity in vitro, which was also demonstrated in vivo on ktr4:NTR-hKikGR zebrafish. Upon investigating the underlying mechanism, we found that SvMEs may alleviate oxidant stress and accelerate α-synuclein degradation and then alleviate PD-like symptoms. Antioxidant-related genes (sod1, gss, gpx4a, gclm, and cat) implied that the SvMEs exhibited anti-PD activity due to the antioxidation mechanism. Finally, upon analysis of chemical composition of SvMEs by liquid chromatography-mass spectrometry, we identified 10 compounds that are plausibly responsible for the anti-PD-like effect of SvMEs. On the limiting part, the finding of the study would have been more robust had we investigated the protein expression of genes related to PD and oxidative stress and compared the effects of SvMEs with any standard anti-PD therapy. Despite this, our results indicated that SvMEs possess anti-PD effects, indicating SvMEs as a potential candidate that is worth exploring further in this avenue.

Pain-Related Abnormal Neuronal Synchronization of the Nucleus Accumbens in Parkinson’s Disease

Patients with Parkinson’s disease (PD) often experience pain, which fluctuates in “on” and “off” states, but the underlying mechanism is unclear. The nucleus accumbens (NAc) is a central component of the mesolimbic dopaminergic pathway involved in pain processing. We conducted resting-state functional magnetic resonance imaging (rsfMRI) analysis to explore the relationship between the neuronal synchronization of NAc with pain-related brain regions and pain intensity in “on” and “off” states. We assessed 23 patients with sporadic PD based on rsfMRI and pain intensity using the revised Short-Form McGill Pain Questionnaire. Patients with PD displayed higher pain intensity scores in the “off” state than in the “on” state. The pain intensity in the “off” state was substantially correlated with the functional connectivity (FC) between the NAc and primary motor/sensory cortices and contralateral NAc. Changes in pain intensity from the “on” to “off” state displayed correlations with those between the right (rNA) and left NAc (lNAc) and the right precentral gyrus (rPreCG) /right insular cortex (rIC) from the “off” to “on” state. Aberrant bilateral NAc and rNAc–rPreCG/rIC FC in the “off” state were closely related to pain symptoms developed from the “on” to “off” states. These results suggest that the NAc in the mesolimbic pathway is related to pain in PD and may help understand the mechanism of pain development in patients with PD.

Management of Sleep Disturbances in Parkinson's Disease

Parkinson's disease (PD) is defined by its motor symptoms rigidity, tremor, and akinesia. However, non-motor symptoms, particularly autonomic disorders and sleep disturbances, occur frequently in PD causing equivalent or even greater discomfort than motor symptoms effectively decreasing quality of life in patients and caregivers. Most common sleep disturbances in PD are insomnia, sleep disordered breathing, excessive daytime sleepiness, REM sleep behavior disorder, and sleep-related movement disorders such as restless legs syndrome. Despite their high prevalence, therapeutic options in the in- and outpatient setting are limited, partly due to lack of scientific evidence. The importance of sleep disturbances in neurodegenerative diseases has been further emphasized by recent evidence indicating a bidirectional relationship between neurodegeneration and sleep. A more profound insight into the underlying pathophysiological mechanisms intertwining sleep and neurodegeneration might lead to unique and individually tailored disease modifying or even neuroprotective therapeutic options in the long run. Therefore, current evidence concerning the management of sleep disturbances in PD will be discussed with the aim of providing a substantiated scaffolding for clinical decisions in long-term PD therapy.

Effects of safinamide adjunct therapy on pain in patients with Parkinson's disease: Post hoc analysis of a Japanese phase 2/3 study

INTRODUCTION

The non-dopaminergic and dopaminergic actions of safinamide may alleviate pain in patients with Parkinson's disease (PD). We investigated the efficacy of safinamide for pain when administered as an adjunct to levodopa in Japanese patients with PD.

METHODS

This was a post hoc analysis of a phase 2/3 clinical study of safinamide in Japanese patients with PD who were experiencing wearing-off. Pain was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) Part II 'sensory symptoms' item 17, on a scale of 0-4, and the 39-item Parkinson's Disease Questionnaire (PDQ-39) 'bodily discomfort' domain score. Subgroup analyses, according to baseline symptoms and concomitant medications, were also performed.

RESULTS

Least square (LS) mean changes in the UPDRS item 17 score from baseline to Week 24 in the placebo, safinamide 50-mg and safinamide 100-mg groups during the OFF phase were 0.08, -0.15 (p = 0.0133 vs placebo) and -0.18 (p = 0.0054), respectively, and during the ON phase were 0.04, -0.08 (p = 0.0529) and -0.08 (p = 0.0505), respectively. Changes from baseline to Week 24 in PDQ-39 'bodily discomfort' scores were not significantly different in safinamide groups vs placebo. The presence of moderate-to-severe bradykinesia or early-morning dystonia at baseline resulted in numerically greater effect sizes in UPDRS item 17 scores during the OFF phase.

CONCLUSIONS

Safinamide 50 mg and 100 mg reduced the UPDRS item 17 score in patients with PD, especially during the OFF phase. Patients with moderate-to-severe bradykinesia and early-morning dystonia may benefit from safinamide treatment.

Neuronal Dynamics of Pain in Parkinson's Disease

Pain is an important non-motor symptom of Parkinson’s disease (PD). It negatively impacts the quality of life. However, the pathophysiological mechanisms underlying pain in PD remain to be elucidated. This study sought to use electroencephalographic (EEG) coherence analysis to compare neuronal synchronization in neuronal networks between patients with PD, with and without pain. Twenty-four patients with sporadic PD were evaluated for the presence of pain. Time-frequency and coherence analyses were performed on their EEG data. Whole-brain and regional coherence were calculated and compared between pain-positive and pain-negative patients. There was no significant difference in the whole-brain coherence between the pain-positive and pain-negative groups. However, temporal–temporal coherence differed significantly between the two groups (p = 0.031). Our findings indicate that aberrant synchronization of inter-temporal regions is involved in PD-related pain. This will further our understanding of the mechanisms underlying pain in PD.

Taurine improves neuron injuries and cognitive impairment in a mouse Parkinson's disease model through inhibition of microglial activation

Clinical and experimental findings support the view that activation of hippocampus microglia through NADPH oxidase contributes to cognitive impairment in Parkinson's disease (PD). Taurine, an antioxidant, displays an exclusive physical property on brain function, such as learning and memory. To date, the role of taurine in improving cognitive impairment in PD is not fully uncovered. Hence, we evaluated the protective effect of taurine on cognitive ability and explored the related mechanism in the model built by paraquat and maneb (P + M)-induced PD mice. Then the ability of learning and memory was observed by Morris water maze, neuron loss was evaluated by immunohistochemistry in hippocampus, the level of postsynaptic density 95 (PSD95) and microglia activation was assessed by immunostaining, the molecules (gp91phox, p47phox, mac1, p-Src/Src and p-Erk/Erk) were examined by western blot. The results showed that taurine could alleviate the impairments in learning and memory induced by P + M injection in mice (decreased escape latency on day 4, P < 0.01; decreased swimming distance on day 4, P < 0.05; increased percent time in target quadrant, P < 0.05), corresponding with activation of microglia (decreased IBa-1 density, P < 0.001; decreased the protein expression of p47phox, P < 0.05; decreased protein expression of gp91phox, P < 0.01; decreased p-Src/Src, P < 0.01; decreased p-Erk/Erk, P < 0.01; decreased mac 1, P < 0.01), decreased neuron loss (increased number of NeurN+ neuron, P < 0.001; increased protein expression of NeruN, P < 0.01; decreased protein expression of caspase 3, P < 0.01) and increased PSD95 level in hippocampus (P < 0.01). The results indicated that mac1 and Src-Erk signaling was involved in increased NADPH oxidase expression in hippocampus microglia of P + M mice, and taurine could improve injuries in learning and memory through mac1 reduction. The new findings in mac1 triggering hippocampal microglia NADPH oxidase through Src/Erk pathway of the present study might provide a therapy target for PD.

Triggers and alleviating factors for fatigue in Parkinson's disease

BACKGROUND

Fatigue is common in Parkinson's Disease, but few effective treatments are available for it. Exploring triggers and alleviating factors, including effects of exercise, could inform development of management strategies for Parkinson's Disease fatigue.

OBJECTIVES

To examine triggers and alleviating factors for fatigue reported by individuals with Parkinson's Disease, including perceived effect of exercise.

METHODS

A sample of individuals with self-reported Parkinson's Disease participating in the study Fox Insight were administered an online survey. The survey included the Parkinson's Fatigue Scale, the Physical Activity Scale for the Elderly, and multiple-choice questions about triggers and alleviating factors for fatigue.

RESULTS

Among the sample of 1,029 individuals with Parkinson's disease, mean (standard deviation (SD)) age was 67.4 (9.3) years, 44.0% were female. Parkinson's Fatigue Scale score ranged from 16-80, mean (SD) 48.8 (16.2). Poor sleep (62.1%) and physical exertion (45.1%) were frequently reported triggers for fatigue. Coping strategies including sitting quietly (58.1%), laying down with or without napping, and exercise (20%). Physical Activity Scale for the Elderly scores were higher in those who reported that exercise alleviated their fatigue (49.7%) compared to those who reported it worsened their fatigue (18.9%) (mean (SD) score 158.5 (88.8) vs 119.8 (66.6) respectively; p<0.001).

CONCLUSIONS

Several behavioral and environmental triggers and alleviating strategies for fatigue are reported by individuals with Parkinson's disease. Many feel that exercise alleviates fatigue, though the relationship between exercise and fatigue in Parkinson's Disease appears complex. This exploratory study may inform future development of treatments or coping strategies for Parkinson's disease fatigue.

Animal Models of Metabolic Disorders in the Study of Neurodegenerative Diseases: An Overview

The incidence of metabolic disorders, as well as of neurodegenerative diseases—mainly the sporadic forms of Alzheimer’s and Parkinson’s disease—are increasing worldwide. Notably, obesity, diabetes, and hypercholesterolemia have been indicated as early risk factors for sporadic forms of Alzheimer’s and Parkinson’s disease. These conditions share a range of molecular and cellular features, including protein aggregation, oxidative stress, neuroinflammation, and blood-brain barrier dysfunction, all of which contribute to neuronal death and cognitive impairment. Rodent models of obesity, diabetes, and hypercholesterolemia exhibit all the hallmarks of these degenerative diseases, and represent an interesting approach to the study of the phenotypic features and pathogenic mechanisms of neurodegenerative disorders. We review the main pathological aspects of Alzheimer’s and Parkinson’s disease as summarized in rodent models of obesity, diabetes, and hypercholesterolemia.

Non-motor symptom burden is strongly correlated to motor complications in patients with Parkinson's disease

BACKGROUND AND PURPOSE

The objective of this study was to analyze the relationship between motor complications and non-motor symptom (NMS) burden in a population of patients with Parkinson's disease (PD) and also in a subgroup of patients with early PD.

METHODS

Patients with PD from the COPPADIS cohort were included in this cross-sectional study. NMS burden was defined according to the Non-Motor Symptoms Scale (NMSS) total score. Unified Parkinson's Disease Rating Scale (UPDRS) part IV was used to establish motor complication types and their severity. Patients with ≤5 years of symptoms from onset were included as patients with early PD.

RESULTS

Of 690 patients with PD (62.6 ± 8.9 years old, 60.1% males), 33.9% and 18.1% presented motor fluctuations and dyskinesia, respectively. The NMS total score was higher in patients with motor fluctuations (59.2 ± 43.1 vs. 38.3 ± 33.1; P < 0.0001) and dyskinesia (63.5 ± 40.7 vs. 41.4 ± 36.3; P < 0.0001). In a multiple linear regression model and after adjustment for age, sex, disease duration, Hoehn & Yahr stage, UPDRS-III score and levodopa equivalent daily dose, UPDRS-IV score was significantly related to a higher NMSS total score (β = 0.27; 95% confidence intervals, 2.81-5.61; P < 0.0001), as it was in a logistic regression model on dichotomous NMSS total score (≤40, mild or moderate vs. >40, severe or very severe) (odds ratio, 1.31; 95% confidence intervals, 1.17-1.47; P < 0.0001). In the subgroup of patients with early PD (n = 396; mean disease duration 2.7 ± 1.5 years), motor fluctuations were frequent (18.1%) and similar results were obtained.

CONCLUSIONS

Motor complications were frequent and were associated with a greater NMS burden in patients with PD even during the first 5 years of disease duration.

Effectiveness and safety of opicapone in Parkinson's disease patients with motor fluctuations: the OPTIPARK open-label study

BACKGROUND

The efficacy and safety of opicapone, a once-daily catechol-O-methyltransferase inhibitor, have been established in two large randomized, placebo-controlled, multinational pivotal trials. Still, clinical evidence from routine practice is needed to complement the data from the pivotal trials.

METHODS

OPTIPARK (NCT02847442) was a prospective, open-label, single-arm trial conducted in Germany and the UK under clinical practice conditions. Patients with Parkinson's disease and motor fluctuations were treated with opicapone 50 mg for 3 (Germany) or 6 (UK) months in addition to their current levodopa and other antiparkinsonian treatments. The primary endpoint was the Clinician's Global Impression of Change (CGI-C) after 3 months. Secondary assessments included Patient Global Impressions of Change (PGI-C), the Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire (PDQ-8), and the Non-Motor Symptoms Scale (NMSS). Safety assessments included evaluation of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs).

RESULTS

Of the 506 patients enrolled, 495 (97.8%) took at least one dose of opicapone. Of these, 393 (79.4%) patients completed 3 months of treatment. Overall, 71.3 and 76.9% of patients experienced any improvement on CGI-C and PGI-C after 3 months, respectively (full analysis set). At 6 months, for UK subgroup only (n = 95), 85.3% of patients were judged by investigators as improved since commencing treatment. UPDRS scores at 3 months showed statistically significant improvements in activities of daily living during OFF (mean ± SD change from baseline: - 3.0 ± 4.6, p < 0.0001) and motor scores during ON (- 4.6 ± 8.1, p < 0.0001). The mean ± SD improvements of - 3.4 ± 12.8 points for PDQ-8 and -6.8 ± 19.7 points for NMSS were statistically significant versus baseline (both p < 0.0001). Most of TEAEs (94.8% of events) were of mild or moderate intensity. TEAEs considered to be at least possibly related to opicapone were reported for 45.1% of patients, with dyskinesia (11.5%) and dry mouth (6.5%) being the most frequently reported. Serious TEAEs considered at least possibly related to opicapone were reported for 1.4% of patients.

CONCLUSIONS

Opicapone 50 mg was effective and generally well-tolerated in PD patients with motor fluctuations treated in clinical practice.

TRIAL REGISTRATION

Registered in July 2016 at clinicaltrials.gov (NCT02847442).

Inhibition of NADPH oxidase by apocynin prevents learning and memory deficits in a mouse Parkinson's disease model

The activation of NADPH oxidase contributes to dopaminergic neurodegeneration and motor deficits in Parkinson's disease (PD). However, whether NADPH oxidase is involved in non-motor symptoms, especially cognitive dysfunction in PD remains unknown. This study is undertaken to characterize the effects of inhibition of NADPH oxidase by a widely used NADPH oxidase inhibitor apocynin on learning and memory deficits in paraquat and maneb-induced mouse PD model. Results showed that mice injected with paraquat and maneb displayed impairments of spatial learning and memory, which was associated with reduced tyrosine hydroxylase expression as well as increased neurodegeneration, synaptic loss, α-synuclein expression and Ser129-phosphorylation in the hippocampus. Interestingly, apocynin treatment significantly ameliorated learning and memory deficits as well as hippocampal neurodegeneration and α-synuclein pathology in mice treated with these two pesticides. Mechanistically, we found that apocynin mitigated paraquat and maneb-induced NADPH oxidase activation and related oxidative stress. Furthermore, reduced microglial activation and M1 polarization were observed in apocynin and paraquat and maneb co-treated mice compared with paraquat and maneb alone group. Finally, apocynin inhibited the activation of signal transducers and activators of transcription 1 (STAT1) and nuclear factor kappa B (NF-κB) pathways, two key regulatory factors for microglial M1 inflammatory responses, in paraquat and maneb-treated mice. Altogether, our findings implied that NADPH oxidase mediates learning and memory deficits in PD, and inhibition of NADPH oxidase by apocynin blocks impairments of learning and memory via the suppression of oxidative stress and neuroinflammation.