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Insomnia is a frequent complaint of patients with Parkinson's disease, and it negatively affects quality of life. Drugs that improve both sleep and parkinsonism would be of major benefit to patients with Parkinson's disease-related insomnia. We aimed to test the safety and efficacy of subcutaneous night-time only apomorphine infusion in patients with Parkinson's disease and insomnia. We did a randomised, multicentre, double-blind, placebo-controlled, crossover trial in 11 expert centres in Parkinson's disease and sleep centres in France. Participants aged 35–90 years with fluctuating Parkinson's disease and moderate to severe insomnia (Insomnia Severity Index score ≥15) were randomly assigned to either first receive night-time subcutaneous apomorphine (up to 5 mg/h) or matching placebo. Randomisation was done using a computer-generated plan in blocks of four, stratified by centre. This first intervention was followed by a 14-night washout period, then crossover to the other intervention. The treatment periods consisted of a 10-night titration phase followed by a 7-night fixed-dose phase. The dose was adjusted during the titration phase on the basis of a daily telephone call assessing sleep quality and treatment tolerability. The primary efficacy endpoint was the difference in Parkinson's disease sleep scale (PDSS) scores from the beginning to the end of each treatment period. Analysis was done on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, NCT02940912. Between Jan 31, 2017, and Jan 29, 2021, 46 participants were enrolled. 25 (54%) patients were randomly assigned to receive apomorphine first and 21 (46%) patients to receive placebo first. Mean change in PDSS score was significantly greater with night-time apomorphine infusion (15·18 [SD 24·34]) compared with placebo (5·23 [21·52]; treatment effect 9·95 [95% CI 0·88–19·03]; p=0·041). Adverse events were reported in 25 (54%) participants during the apomorphine period and in 17 (37%) participants during the placebo period (p=0·16). Apomorphine was associated with more frequent dizziness than was placebo (seven [15%] vs 0; p=0·041). Subcutaneous night-time only apomorphine infusion improved sleep disturbances according to difference on PDSS score, with an overall safety profile consistent with previous studies in Parkinson's disease. This treatment might be useful to manage sleep disturbances in patients with advanced Parkinson's disease and moderate to severe insomnia. Orkyn and Aguettant Pharma. For the French translation of the abstract see Supplementary Materials section.

Repeated association of drugs of abuse with context leads to long-lasting behavioral responses that reflect reward-controlled learning and participate in the establishment of addiction. Reactivation of consolidated memories is known to produce a reconsolidation process during which memories undergo a labile state. We investigated whether reexposure to drugs had similar effects. Cocaine administration activates extracellular signal-regulated kinase (ERK) in the striatum, and ERK activation is required for the acquisition of cocaine-induced conditioned place preference (CPP). When mice previously conditioned for cocaine-place preference were reexposed to cocaine in the drug-paired compartment after systemic administration of 51327, an inhibitor of ERK activation, CPP response was abolished 24 h later. This procedure also abolished the phosphorylation of ERK and glutamate receptor-I observed in the ventral and dorsal striatum, 24 h later, during CPP test. Erasure of CPP by 51327 required the combination of cocaine administration and drug-paired context and did not result from enhanced extinction. Similarly, reexposure to morphine in the presence of SL327 long-lastingly abolished response of previously learned morphine-CPP. The effects of SL327 on cocaine- or morphine-CPP were reproduced by protein synthesis inhibition. In contrast, protein synthesis inhibition did not alter previously acquired locomotor sensitization to cocaine. Our findings show that an established CPP can be disrupted when reactivation associates both the conditioned context and drug administration. This process involves ERK, and systemic treatment preventing ERK activation during reexposure erases the previously learned behavioral response. These results suggest potential therapeutic strategies to explore in the context of addiction.

Appetite and drug addiction Disruptions in dopamine signalling have been implicated in psychiatric disorders, such as schizophrenia and drug addiction. The phosphoprotein DARPP-32 is a prominent mediator of dopamine signalling in the striatum, a part of the brain where dopaminergic activation has been linked to reward and learning. Now a novel signal transduction cascade involving nuclear accumulation of DARPP-32 has been discovered, induced by both drugs of abuse and natural stimuli such as food. Disruption of this cascade alters the behavioural effects of the drugs and decreases motivation for food, suggesting a role for this mechanism in the in vivo actions of dopamine signalling. Dopamine orchestrates motor behaviour and reward-driven learning. Perturbations of dopamine signalling have been implicated in several neurological and psychiatric disorders, and in drug addiction. The actions of dopamine are mediated in part by the regulation of gene expression in the striatum, through mechanisms that are not fully understood. Here we show that drugs of abuse, as well as food reinforcement learning, promote the nuclear accumulation of 32-kDa dopamine-regulated and cyclic-AMP-regulated phosphoprotein (DARPP-32). This accumulation is mediated through a signalling cascade involving dopamine D1 receptors, cAMP-dependent activation of protein phosphatase-2A, dephosphorylation of DARPP-32 at Ser 97 and inhibition of its nuclear export. The nuclear accumulation of DARPP-32, a potent inhibitor of protein phosphatase-1, increases the phosphorylation of histone H3, an important component of nucleosomal response. Mutation of Ser 97 profoundly alters behavioural effects of drugs of abuse and decreases motivation for food, underlining the functional importance of this signalling cascade.

Tau is normally a highly soluble phosphoprotein found predominantly in neurons. Six different isoforms of tau are expressed in the adult human CNS. Under pathological conditions, phosphorylated tau aggregates are a defining feature of neurodegenerative disorders called tauopathies. Recent findings have suggested a potential role of the gut-brain axis in CNS homeostasis, and therefore we set out to examine the isoform profile and phosphorylation state of tau in the enteric nervous system (ENS) under physiological conditions and in tauopathies. Surgical specimens of human colon from controls, Parkinson’s disease (PD) and progressive supranuclear palsy (PSP) patients were analyzed by Western Blot and immunohistochemistry using a panel of anti-tau antibodies. We found that adult human ENS primarily expresses two tau isoforms, localized in the cell bodies and neuronal processes. We did not observe any difference in the enteric tau isoform profile and phosphorylation state between PSP, PD and control subjects. The htau mouse model of tauopathy also expressed two main isoforms of human tau in the ENS, and there were no apparent differences in ENS tau localization or phosphorylation between wild-type and htau mice. Tau in both human and mouse ENS was found to be phosphorylated but poorly susceptible to dephosphorylation with lambda phosphatase. To investigate ENS tau phosphorylation further, primary cultures from rat enteric neurons, which express four isoforms of tau, were pharmacologically manipulated to show that ENS tau phosphorylation state can be regulated, at least in vitro. Our study is the first to characterize tau in the rodent and human ENS. As a whole, our findings provide a basis to unravel the functions of tau in the ENS and to further investigate the possibility of pathological changes in enteric neuropathies and tauopathies.

Abstract Immunohistochemical (IHC) α-synuclein (Asyn) pathology in peripheral biopsies may be a biomarker of Parkinson disease (PD). The multi-center Systemic Synuclein Sampling Study (S4) is evaluating IHC Asyn pathology within skin, colon and submandibular gland biopsies from 60 PD and 20 control subjects. Asyn pathology is being evaluated by a blinded panel of specially trained neuropathologists. Preliminary work assessed 2 candidate immunoperoxidase methods using a set of PD and control autopsy-derived sections from formalin-fixed, paraffin-embedded blocks of the 3 tissues. Both methods had 100% specificity; one, utilizing the 5C12 monoclonal antibody, was more sensitive in skin (67% vs 33%), and was chosen for further use in S4. Four trainee neuropathologists were trained to perform S4 histopathology readings; in subsequent testing, their scoring was compared to that of the trainer neuropathologist on both glass slides and digital images. Specificity and sensitivity were both close to 100% with all readers in all tissue types on both glass slides and digital images except for skin, where sensitivity averaged 75% with digital images and 83.5% with glass slides. Semiquantitative (0-3) density score agreement between trainees and trainer averaged 67% for glass slides and 62% for digital images.

The observation showing that Lewy type synucleinopathy (LTS), the pathological hallmark of Parkinson’s disease (PD), is found in the gut of almost all PD subjects led to a substantial amount of research to develop a diagnostic procedure in living patients based on endoscopically obtained gastrointestinal biopsies. However, the existing studies have provided conflicting results regarding the sensitivity and specificity of gastrointestinal biopsies for the detection of LTS. We therefore undertook a multi-center staining and blinded judging of a common set of slides from colonic biopsies to determine the optimal protocol for the detection of LTS. Four different immunohistochemical methods, developed in four separate expert laboratories, were evaluated for their sensitivity and specificity to detect enteric LTS. Test sets of formalin-fixed, paraffin-embedded sections from biopsies of 9 PD subjects and 3 controls were stained with the 4 methods and graded by 4 different observers. Four types of staining morphology (granular staining in the lamina propria , perivascular/vascular wall staining in the submucosa, lacy-granular pattern in the submucosa and epithelial cell nuclear staining) were variably observed in the slides stained by the 4 methods. Positive alpha-synuclein staining was observed by all 5 judges in most of the slides from control cases, regardless of the staining methods that were used. Moreover, none of the tested method or staining pattern had a specificity and sensitivity more than 80 % regarding to PD. Overall, our study suggest that the tested methods are not adequate for the prediction of PD using gastrointestinal biopsies. Future studies are warranted to test new immunostaining methods.

Conventional oral levodopa therapy for the treatment of Parkinson's disease can be associated with variations in plasma concentrations. Levodopa infusion strategies might provide more consistent drug delivery and fewer motor fluctuations. We aimed to assess the safety and efficacy of a continuous 24 h/day subcutaneous infusion of ND0612 (a levodopa–carbidopa solution) compared with oral immediate-release levodopa–carbidopa for the treatment of motor fluctuations in people with Parkinson's disease. We conducted a phase 3, randomised, double-blind, double-dummy, active-controlled, multicentre trial at 117 academic and community neurology sites in 16 countries, including in Europe, Israel, and the USA. Eligible participants were men and women aged 30 years or older with a diagnosis of Parkinson's disease (Hoehn and Yahr stage ≤3 in the on state) who experienced at least 2·5 h/day of off time. Participants underwent an open-label run-in phase (<12 weeks), during which time optimal regimens were established for both oral immediate-release levodopa–carbidopa and for 24 h/day subcutaneous ND0612 infusion (levodopa–carbidopa 60·0/7·5 mg/mL), with supplemental oral levodopa–carbidopa if needed. Participants were then randomly assigned (1:1) to 12 weeks of double-blind treatment with their optimised regimen of either subcutaneous ND0612 or oral levodopa–carbidopa, with matching oral or subcutaneous placebo given as required to maintain blinding. Randomisation was done via an interactive web response system, stratified by region, using a permuted block schedule. Participants, study partners, treating investigators, study site personnel, and the sponsor were masked to treatment group allocation. The primary efficacy endpoint was the change from baseline (ie, time of randomisation, when all patients were receiving an optimised open-label ND0612 regimen) to end of the double-blind phase in total daily on time without troublesome dyskinesia, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, NCT04006210, and is complete. Between Sept 30, 2019, and April 8, 2022, 381 participants were enrolled, of whom 259 (68%) were randomly assigned, 128 (49%) to subcutaneous ND0612 and 131 (51%) to oral levodopa–carbidopa. 243 (94%) participants completed the study. Treatment with subcutaneous ND0612 provided an additional 1·72 h (95% CI 1·08 to 2·36) of on time without troublesome dyskinesia compared with oral levodopa–carbidopa (change from baseline of –0·48 h [–0·94 to –0·02] with subcutaneous ND0612 vs –2·20 h [–2·65 to –1·74] with oral levodopa–carbidopa; p<0·0001). Significant treatment differences favouring subcutaneous ND0612 were also found in the first four of nine prespecified hierarchical outcomes of daily off time (–1·40 h [95% CI –1·99 to –0·80]), Movement Disorders Society-Unified Parkinson's Disease Rating Scale part II scores (–3·05 [–4·28 to –1·81]), Patients Global Impression of Change (odds ratio [OR] 5·31 [2·67 to 10·58]), and Clinical Global Impression of Improvement (OR 7·23 [3·57 to 14·64]). Hierarchical testing ended after the fourth secondary endpoint. Adverse events were reported by 287 (89%) of 322 participants during open-label ND0612 optimisation, and by 103 (80%) of 128 in the ND0612 group and 97 (74%) of 131 in the oral levodopa–carbidopa group during the double-blind phase. The most common adverse events were infusion-site reactions (266 [83%] participants during open-label ND0612, and 73 [57%] in the ND0612 group vs 56 [43%] in the oral levodopa–carbidopa group during the double-blind phase), most of which were mild. Serious adverse events in four participants in the ND0612 group were related to study treatment (infusion-site cellulitis [n=2], infusion-site abscess and infusion-site ulcer [n=1]; and paraesthesia and peripheral sensorimotor neuropathy [n=1]). One participant in the ND0612 group died during the double-blind phase, but the death was not related to study treatment (fall leading to traumatic brain injury). Results of this phase 3 study showed that subcutaneous ND0612 used in combination with oral immediate-release levodopa–carbidopa increased on time without troublesome dyskinesia and reduced off time, with a favourable benefit–risk profile. ND0612 might offer a safe and efficacious subcutaneous levodopa infusion approach to managing motor fluctuations in people with Parkinson's disease. The ongoing open-label extension phase will provide further information on the long-term efficacy and safety of treatment. NeuroDerm.

Currently, no treatments available for Parkinson’s disease (PD) can slow PD progression. At the early stage of the disease, only a subset of individuals with PD progress quickly, while the majority have a slowly progressive form of the disease. In developing treatments that aim to slow PD progression, clinical trials aim to include individuals who are likely to progress faster, such that a treatment effect, if one exists, can be identified easier and earlier. The aim of the present study was to identify baseline predictors of clinical progression in early PD. We analyzed 12-month data acquired from the PASADENA trial Part 1 (NCT03100149, n = 76 participants who were allocated to the placebo arm and did not start symptomatic therapy) and the Parkinson’s Progression Markers Initiative (PPMI) study ( n = 139 demographically and clinically matched participants). By using ridge regression models including clinical characteristics, imaging, and non-imaging biomarkers, we found that Hoehn and Yahr stage and dopamine transporter single-photon emission computed tomography specific binding ratios (Dat-SPECT SBR) in putamen ipsilateral to the side of motor symptom onset predicted PD progression at the early stage of the disease. Further studies are needed to confirm the validity of these predictors to identify with high accuracy individuals with early PD with a faster progression phenotype.

Objective To assess amantadine use and associated factors in the patients with Parkinson’s disease (PD). Background Immediate-release amantadine is approved for the treatment of PD and is largely used in clinical practice to treat “levodopa-induced dyskinesia (LIDs). Its use varies according to countries and PD stages. The prospective NS-Park cohort collects features of PD patients followed by 26 French PD Expert Centres. Methods Variables used for the analyses included demographics, motor and non-motor PD symptoms and motor complications [motor fluctuations (MFs), LIDs)], antiparkinsonian pharmacological classes and levodopa equivalent daily dose (LEDD). We evaluated: (i) prevalence of amantadine use and compared clinical features of amantadine users vs. non-users (cross-sectional analysis); (ii) factors associated with amantadine initiation (longitudinal analysis); (iii) amantadine effect on LIDs, MFs, apathy, impulse control disorders and freezing of gait (Fog) (longitudinal analysis). Results Amantadine use prevalence was 12.6% (1,585/12,542, median dose = 200 mg). Amantadine users were significantly younger, with longer and more severe PD symptoms, greater LEDD and more frequent use of device-aided/surgical treatment. Factors independently associated with amantadine initiation were younger age, longer PD duration, more frequent LIDs, MFs and FoG, higher LEDD and better cognitive function. 9 of the 658 patients on amantadine had stopped it at the following visit, after 12–18 months (1.3%). New users of amantadine presented a higher improvement in LIDs and MF compared to amantadine never users. Conclusions About 12% of PD patients within the French NS-Park cohort used amantadine, mostly those with younger age and more severe PD. Amantadine initiation was associated with a subsequent reduction in LIDs and MFs.

Repeated association of drugs of abuse with context leads to long-lasting behavioral responses that reflect reward-controlled learning and participate in the establishment of addiction. Reactivation of consolidated memories is known to produce a reconsolidation process during which memories undergo a labile state. We investigated whether reexposure to drugs had similar effects. Cocaine administration activates extracellular signal-regulated kinase (ERK) in the striatum, and ERK activation is required for the acquisition of cocaine-induced conditioned place preference (CPP). When mice previously conditioned for cocaine-place preference were reexposed to cocaine in the drug-paired compartment after systemic administration of SL327, an inhibitor of ERK activation, CPP response was abolished 24 h later. This procedure also abolished the phosphorylation of ERK and glutamate receptor-1 observed in the ventral and dorsal striatum, 24 h later, during CPP test. Erasure of CPP by SL327 required the combination of cocaine administration and drug-paired context and did not result from enhanced extinction. Similarly, reexposure to morphine in the presence of SL327 long-lastingly abolished response of previously learned morphine-CPP. The effects of SL327 on cocaine- or morphine-CPP were reproduced by protein synthesis inhibition. In contrast, protein synthesis inhibition did not alter previously acquired locomotor sensitization to cocaine. Our findings show that an established CPP can be disrupted when reactivation associates both the conditioned context and drug administration. This process involves ERK, and systemic treatment preventing ERK activation during reexposure erases the previously learned behavioral response. These results suggest potential therapeutic strategies to explore in the context of addiction.