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The innate immune system is implicated in Parkinson’s disease (PD), but peripheral in-vivo clinical evidence of the components and driving mechanisms involved and their relationship with clinical heterogeneity and progression to dementia remain poorly explored. We examined changes in peripheral innate immune-related markers in PD cases (n = 41) stratified according to risk of developing early dementia. ‘Higher Risk’(HR) (n = 23) and ‘Lower Risk’ (LR) (n = 18) groups were defined according to neuropsychological predictors and MAPT H1/H2 genotype, and compared to age, gender and genotype-matched controls. Monocyte subsets and expression of key surface markers were measured using flow cytometry. Serum markers including alpha-synuclein, inflammasome-related caspase-1 and bacterial translocation-related endotoxin were measured using quantitative immuno-based assays. Specific markers were further investigated using monocyte assays and validated in plasma samples from a larger incident PD cohort (n = 95). We found that classical monocyte frequency was elevated in PD cases compared to controls, driven predominantly by the HR group, in whom Toll-Like Receptor (TLR)4+ monocytes and monocyte Triggering Receptor Expressed on Myeloid cells-2 (TREM2) expression were also increased. Monocyte Human Leukocyte Antigen (HLA)-DR expression correlated with clinical variables, with lower levels associated with worse cognitive/motor performance. Notably, monocyte changes were accompanied by elevated serum bacterial endotoxin, again predominantly in the HR group. Serum alpha-synuclein and inflammasome-related caspase-1 were decreased in PD cases compared to controls regardless of group, with decreased monocyte alpha-synuclein secretion in HR cases. Further, alpha-synuclein and caspase-1 correlated positively in serum and monocyte lysates, and in plasma from the larger cohort, though no associations were seen with baseline or 36-month longitudinal clinical data. Principal Components Analysis of all monocyte and significant serum markers indicated 3 major components. Component 1 (alpha-synuclein, caspase-1, TLR2+ monocytes) differentiated PD cases and controls in both groups, while Component 2 (endotoxin, monocyte TREM2, alpha-synuclein) did so predominantly in the HR group. Component 3 (classical monocytes, alpha-synuclein) also differentiated cases and controls overall in both groups. These findings demonstrate that systemic innate immune changes are present in PD and are greatest in those at higher risk of rapid progression to dementia. Markers associated with PD per-se (alpha-synuclein, caspase-1), differ from those related to cognitive progression and clinical heterogeneity (endotoxin, TREM2, TLR4, classical monocytes, HLA-DR), with mechanistic and therapeutic implications. Alpha-synuclein and caspase-1 are associated, suggesting inflammasome involvement common to all PD, while bacterial translocation associated changes may contribute towards progression to Parkinson’s dementia. Additionally, HLA-DR-associated variations in antigen presentation/clearance may modulate existing clinical disease.

Functional dependency in basic activities of daily living (ADLs) is a key outcome in Parkinson's disease (PD). We aimed to define dependency in PD, using the original and MDS versions of the Unified Parkinson's Disease Rating Scale (UPDRS).We developed two algorithms to define dependency from items of UPDRS Part 2 and MDS-UPDRS Part 2 relating to basic ADLs (feeding, dressing, hygiene and walking, and getting out of a chair). We validated both algorithms using data from 1110 patients from six community-based PD incidence cohorts, testing concurrent validity, convergent validity, and predictive validity.Our optimal algorithm showed high specificity and moderate to high sensitivity versus SchwabEngland80% (specificity 95% [95% confidence interval (CI) 93-97] and sensitivity 65% [95% CI 55-73] at baseline; 88% [95% CI 85-91] and 85% [95% CI 79-97] respectively at five-years follow-up). Convergent validity was demonstrated by strong associations between dependency defined by the algorithm and cognition (MMSE), quality of life (PDQ39), and impairment (UPDRS part 3) (all p 0.001). Algorithm-defined dependency status also predicted mortality: HR for mortality in those dependent vs independent at baseline was 1.6 (95%CI 1.2-2.1) and in those dependent vs independent at five-years' follow-up was 2.2 (1.6-3.0).We have demonstrated the concurrent validity, convergent validity, and predictive validity of a UPDRS-/MDS-UPDRS-based algorithm to define functional dependency in PD. This can be used for studying dependency in any study where UPDRS or MDS-UPDRS part 2 data have been collected.

Constipation is a common but not a universal feature in early PD, suggesting that gut involvement is heterogeneous and may be part of a distinct PD subtype with prognostic implications. We analysed data from the Parkinson’s Incidence Cohorts Collaboration, composed of incident community-based cohorts of PD patients assessed longitudinally over 8 years. Constipation was assessed with the MDS-UPDRS constipation item or a comparable categorical scale. Primary PD outcomes of interest were dementia, postural instability and death. PD patients were stratified according to constipation severity at diagnosis: none (n = 313, 67.3%), minor (n = 97, 20.9%) and major (n = 55, 11.8%). Clinical progression to all three outcomes was more rapid in those with more severe constipation at baseline (Kaplan–Meier survival analysis). Cox regression analysis, adjusting for relevant confounders, confirmed a significant relationship between constipation severity and progression to dementia, but not postural instability or death. Early constipation may predict an accelerated progression of neurodegenerative pathology.

Item does not contain fulltext BACKGROUND: Several reports have identified different patterns of Parkinson's disease progression in individuals carrying missense variants in GBA or LRRK2 genes. The overall contribution of genetic factors to the severity and progression of Parkinson's disease, however, has not been well studied. OBJECTIVES: To test the association between genetic variants and the clinical features of Parkinson's disease on a genomewide scale. METHODS: We accumulated individual data from 12 longitudinal cohorts in a total of 4093 patients with 22,307 observations for a median of 3.81 years. Genomewide associations were evaluated for 25 cross-sectional and longitudinal phenotypes. Specific variants of interest, including 90 recently identified disease-risk variants, were also investigated post hoc for candidate associations with these phenotypes. RESULTS: Two variants were genomewide significant. Rs382940(T>A), within the intron of SLC44A1, was associated with reaching Hoehn and Yahr stage 3 or higher faster (hazard ratio 2.04 [1.58-2.62]; P value = 3.46E-8). Rs61863020(G>A), an intergenic variant and expression quantitative trait loci for alpha-2A adrenergic receptor, was associated with a lower prevalence of insomnia at baseline (odds ratio 0.63 [0.52-0.75]; P value = 4.74E-8). In the targeted analysis, we found 9 associations between known Parkinson's risk variants and more severe motor/cognitive symptoms. Also, we replicated previous reports of GBA coding variants (rs2230288: p.E365K; rs75548401: p.T408M) being associated with greater motor and cognitive decline over time, and an APOE E4 tagging variant (rs429358) being associated with greater cognitive deficits in patients. CONCLUSIONS: We identified novel genetic factors associated with heterogeneity of Parkinson's disease. The results can be used for validation or hypothesis tests regarding Parkinson's disease. (c) 2019 International Parkinson and Movement Disorder Society.

BackgroundSeveral reports have identified different patterns of Parkinson’s disease progression in individuals carrying missense variants in theGBAorLRRK2genes. The overall contribution of genetic factors to the severity and progression of Parkinson’s disease, however, has not been well studied.ObjectivesTo test the association between genetic variants and the clinical features and progression of Parkinson’s disease on a genome-wide scale.MethodsWe accumulated individual data from 12 longitudinal cohorts in a total of 4,093 patients with 25,254 observations over a median of 3.81 years. Genome-wide associations were evaluated for 25 cross-sectional and longitudinal phenotypes. Specific variants of interest, including 90 recently-identified disease risk variants, were also investigated for the associations with these phenotypes.ResultsTwo variants were genome-wide significant. Rs382940(T>A), within the intron ofSLC44A1, was associated with reaching Hoehn and Yahr stage 3 or higher faster (HR 2.04 [1.58, 2.62], P-value = 3.46E-8). Rs61863020(G>A), an intergenic variant and eQTL forADRA2A, was associated with a lower prevalence of insomnia at baseline (OR 0.63 [0,52, 0.75], P-value = 4.74E-8). In the targeted analysis, we found nine associations between known Parkinson’s risk variants and more severe motor/cognitive symptoms. Also, we replicated previous reports ofGBAcoding variants (rs2230288: p.E365K, rs75548401: p.T408M) being associated with greater motor and cognitive decline over time, andAPOEE4 tagging variant (rs429358) being associated with greater cognitive deficits in patients.ConclusionsWe identified novel genetic factors associated with heterogeneity of progression in Parkinson’s disease. The results provide new insights into the pathogenesis of Parkinson’s disease as well as patient stratification for clinical trials.

ObjectiveTo determine if any association between previously identified alleles that confer risk for Parkinson disease and variables measuring disease progression.MethodsWe evaluated the association between 31 risk variants and variables measuring disease progression. A total of 23,423 visits by 4,307 patients of European ancestry from 13 longitudinal cohorts in Europe, North America, and Australia were analyzed.ResultsWe confirmed the importance ofGBAon phenotypes.GBAvariants were associated with the development of daytime sleepiness (p.N370S: hazard ratio [HR] 3.28 [1.69–6.34]) and possible REM sleep behavior (p.T408M: odds ratio 6.48 [2.04–20.60]). We also replicated previously reported associations ofGBAvariants with motor/cognitive declines. The other genotype-phenotype associations include an intergenic variant nearLRRK2and the faster development of motor symptom (Hoehn and Yahr scale 3.0 HR 1.33 [1.16–1.52] for the C allele of rs76904798) and an intronic variant inPMVKand the development of wearing-off effects (HR 1.66 [1.19–2.31] for the C allele of rs114138760). Age at onset was associated withTMEM175variant p.M393T (−0.72 [−1.21 to −0.23] in years), the C allele of rs199347 (intronic region ofGPNMB, 0.70 [0.27–1.14]), and G allele of rs1106180 (intronic region ofCCDC62, 0.62 [0.21–1.03]).ConclusionsThis study provides evidence that alleles associated with Parkinson disease risk, in particularGBAvariants, also contribute to the heterogeneity of multiple motor and nonmotor aspects. Accounting for genetic variability will be a useful factor in understanding disease course and in minimizing heterogeneity in clinical trials.

IntroductionParkinson’s disease (PD) is the most common movement disorder in the elderly and is characterised clinically by bradykinesia, tremor and rigidity. Diagnosing Parkinson’s can be difficult especially in the early stages. High-resolution nigrosome MRI offers promising diagnostic accuracy of patients with established clinical symptoms; however, it is unclear whether this may help to establish the diagnosis in the early stages of PD, when there is diagnostic uncertainty. In this scenario, a single photon emission CT scan using a radioactive dopamine transporter ligand can help to establish the diagnosis, or clinical follow-up may eventually clarify the diagnosis. A non-invasive, cost-effective diagnostic test that could replace this would be desirable. We therefore aim to prospectively test whether nigrosome MRI is as useful as DaTSCAN to establish the correct diagnosis in people with minor or unclear symptoms suspicious for PD.Methods and analysisIn a prospective study we will recruit 145 patients with unclear symptoms possibly caused by Parkinson’s from three movement disorder centres in the UK to take part in the study. We will record the Movement Disorder Society - Unified Parkinson’s Disease Rating Scale, and participants will undergo DaTSCAN and high-resolution susceptibility weighted MRI at a field strength of 3T. DaTSCANs will be assessed visually and semiquantitatively; MRI scans will be visually assessed for signal loss in nigrosome-1 by blinded investigators. We will compare how the diagnosis suggested by MRI compares with the diagnosis based on DaTSCAN and will also validate the diagnosis based on the two tests with a clinical examination performed at least 1 year after the initial presentation as a surrogate gold standard diagnostic test.Ethics and disseminationThe local ethics commission (Health Research Authority East Midlands – Derby Research Ethics Committee) has approved this study (REC ref.: 16/EM/0229). The study is being carried out under the principles of the Declaration of Helsinki (64th, 2013) and Good Clinical Practice standards. We have included a number of 15 research-funded DaTSCAN in the research protocol. This is to compensate for study site-specific National Health Service funding for this investigation in affected patients. We therefore have also obtained approval from the Administration of Radioactive Substances Administration Committee (ARSAC Ref 253/3629/35864). All findings will be presented at relevant scientific meetings and published in peer-reviewed journals, on the study website, and disseminated in lay and social media where appropriate.Trial registration numberNCT03022357; Pre-results.

Carriers of mutations in the glucocerebrosidase gene (GBA) are at increased risk of developing Parkinson's disease. The frequency of GBA mutations in unselected Parkinson's disease populations has not been established. Furthermore, no previous studies have investigated the influence of GBA mutations on the natural history of Parkinson's disease using prospective follow-up. We studied DNA from 262 cases who had been recruited at diagnosis into one of two independent community-based incidence studies of Parkinson's disease. In 121 cases, longitudinal data regarding progression of motor disability and cognitive function were derived from follow-up assessments conducted every 18 months for a median of 71 months. Sequencing of the GBA was performed after two-stage polymerase chain reaction amplification. The carrier frequency of genetic variants in GBA was determined. Baseline demographic and clinical variables were compared between cases who were either GBA mutation carriers, polymorphism carriers or wild-type homozygotes. Cox regression analysis was used to model progression to major motor (Hoehn and Yahr stage 3), and cognitive (dementia) end-points in cases followed longitudinally. We show that in a representative, unselected UK Parkinson's disease population, GBA mutations are present at a frequency of 3.5%. This is higher than the prevalence of other genetic mutations currently associated with Parkinson's disease and indicates that GBA mutations make an important contribution to Parkinson's disease encountered in the community setting. Baseline clinical characteristics did not differ significantly between cases with and without GBA sequence variants. However, the hazard ratio for progression both to dementia (5.7, P = 0.003) and Hoehn and Yahr stage 3 (4.2, P = 0.003) were significantly greater in GBA mutation carriers. We also show that carriers of polymorphisms in GBA which are not generally considered to increase Parkinson's disease risk are at significantly increased risk of progression to Hoehn and Yahr stage 3 (3.2, P = 0.004). Our results indicate that genetic variation in GBA has an important impact on the natural history of Parkinson's disease. To our knowledge, this is the first time a genetic locus has been shown to influence motor progression in Parkinson's disease. If confirmed in further studies, this may indicate that GBA mutation status could be used as a prognostic marker in Parkinson's disease. Elucidation of the molecular mechanisms that underlie this effect will further our understanding of the pathogenesis of the disease and may in turn suggest novel therapeutic strategies.

Background Our understanding of the natural history of idiopathic Parkinson’s disease (PD) remains limited. In the era of potential disease modifying therapies, there is an urgent need for studies assessing the natural evolution of treated PD from onset so that relevant outcome measures can be identified for clinical trials. No previous studies have charted progression in unselected patients followed from the point of diagnosis. Methods A representative cohort of 132 PD patients was followed from diagnosis for up to 7.9 years (mean 5.2 years). Comprehensive clinical and neuropsychological evaluations were performed every 18 months. Disease progression was evaluated using well validated clinical measures (motor progression and development of dyskinesia on the Unified PD Rating Scale and HoehneYahr scale, dementia onset according to DSM-IV criteria). Multi-level linear modelling was used to chart the nature and rate of progression in parkinsonian symptoms and signs over time. The prognostic importance of baseline demogr‘aphic, clinical and genetic variables was evaluated using survival analysis. Results Axial (gait and postural) symptoms evolve more rapidly than other motor features of PD and appear to be the best index of disease progression. Conversely, conventional outcome measures are relatively insensitive to change over time. Earlier onset of postural instability (HoehneYahr stage 3) is strongly associated with increased age at disease onset and has a significant impact on quality of life. Conclusions Dementia risk is associated with increased age, impaired baseline semantic fluency and the MAPT H1/H1 genotype. The efficacy of disease modifying therapies may be more meaningfully assessed in terms of their effects in delaying the major milestones of PD, such as postural instability and dementia, since it is these that have the greatest impact on patients.

Cognitive abnormalities are common in Parkinson's disease, with important social and economic implications. Factors influencing their evolution remain unclear but are crucial to the development of targeted therapeutic strategies. We have investigated the development of cognitive impairment and dementia in Parkinson's disease using a longitudinal approach in a population-representative incident cohort (CamPaIGN study, n = 126) and here present the 5-year follow-up data from this study. Our previous work has implicated two genetic factors in the development of cognitive dysfunction in Parkinson's disease, namely the genes for catechol-O-methyltransferase (COMT Val(158)Met) and microtubule-associated protein tau (MAPT) H1/H2. Here, we have explored the influence of these genes in our incident cohort and an additional cross-sectional prevalent cohort (n = 386), and investigated the effect of MAPT H1/H2 haplotypes on tau transcription in post-mortem brain samples from patients with Lewy body disease and controls. Seventeen percent of incident patients developed dementia over 5 years [incidence 38.7 (23.9-59.3) per 1000 person-years]. We have demonstrated that three baseline measures, namely, age >or=72 years, semantic fluency less than 20 words in 90 s and inability to copy an intersecting pentagons figure, are significant predictors of dementia risk, thus validating our previous findings. In combination, these factors had an odds ratio of 88 for dementia within the first 5 years from diagnosis and may reflect the syndrome of mild cognitive impairment of Parkinson's disease. Phonemic fluency and other frontally based tasks were not associated with dementia risk. MAPT H1/H1 genotype was an independent predictor of dementia risk (odds ratio = 12.1) and the H1 versus H2 haplotype was associated with a 20% increase in transcription of 4-repeat tau in Lewy body disease brains. In contrast, COMT genotype had no effect on dementia, but a significant impact on Tower of London performance, a frontostriatally based executive task, which was dynamic, such that the ability to solve this task changed with disease progression. Hence, we have identified three highly informative predictors of dementia in Parkinson's disease, which can be easily translated into the clinic, and established that MAPT H1/H1 genotype is an important risk factor with functional effects on tau transcription. Our work suggests that the dementing process in Parkinson's disease is predictable and related to tau while frontal-executive dysfunction evolves independently with a more dopaminergic basis and better prognosis.

The search for therapeutic agents that might alter the disease course in Parkinson's disease (PD) is ongoing. One area of particular interest involves neurotrophic factors (NTFs), with those of the glial cell line-derived neurotrophic factor (GDNF) family showing greatest promise. The safety and efficacy of these therapies has recently come into question. Furthermore, many of the key questions pertaining to such therapies, such as the optimal method of delivery, timing of treatment and selection of patients most likely to benefit, remain unanswered.In this review we sought to evaluate the therapeutic potential of NTFs in the treatment of PD. We appraised the evidence provided by both in vitro and in vivo work before proceeding to a critical assessment of the relevant clinical trial data.Relevant literature was identified using a PubMed search of articles published up to October 2007. Search terms included: 'Parkinson's disease', 'Neurotrophic factors', 'BDNF' (Brain-derived neurotrophic factor), 'GDNF' and 'Neurturin'. Original articles were reviewed, and relevant citations from these articles were also appraised.NTF therapy has potential in the treatment of nigrostriatal dysfunction in PD but numerous methodological and safety issues will need to be addressed before this approach can be widely adopted. Furthermore PD is now recognized as being more than a pure motor disorder, and one in which neuronal loss is not just confined to the dopaminergic nigrostriatal system. Non-motor symptomatology in PD is unlikely to benefit from therapies that target only the nigrostriatal system, and this must inform our thinking as to the maximal achievable benefit that NTFs are ever likely to provide.

The early and accurate diagnosis of Parkinson's disease (PD) is the first step towards optimal patient management. The aim of this study was to investigate the major determinants of delayed diagnosis in PD. We recruited a population-representative cohort of 239 newly-diagnosed PD patients who underwent clinical and neuropsychological evaluation. Non-parametric methods were used to define the factors associated with diagnostic delay. The median time from motor symptom onset to primary care physician (PCP) presentation was considerably longer than the time from PCP presentation to PD diagnosis (11 vs. 1 months). Male sex and presenting motor phenotype were independently associated with delayed PCP presentation on Cox regression analysis. Patients presenting with gait disturbance experienced the longest delay, whilst those presenting with tremor had the shortest. In summary, male sex and presenting motor phenotype are key determinants of delayed diagnosis in PD.

Introduction: Cognitive impairment is common in Parkinson's disease (PD), even in the early stages, and appropriate screening tools are needed. Methods: We investigated the utility of the Addenbrooke's Cognitive Examination-Revised for detecting mild cognitive impairment (MCI) in PD in an incident population-representative cohort (n = 132) and investigated the relationship between performance on this instrument and behavior and quality of life (n = 219). Results: Twenty-two percent met criteria for MCI. Receiver operating curve analysis revealed an area under the curve of 0.81. A cutoff

There is a major unmet need for therapies for Parkinson's disease (PD) that go beyond treating symptoms and instead modify the course of the disease. The use of neural transplantation to repair the degenerating dopaminergic nigrostriatal pathway is one strategy by which this might be achieved. A series of small, independent open-label studies initially reported beneficial effects in patients treated with cell transplants derived from the fetal ventral mesencephalon. However, this initial promise was subsequently tempered by negative results from two larger, randomized studies, and the emergence of complications related to the procedure. The reason for these discordant results has been debated and this has led to the development of a new, multicenter, collaborative study--TRANSEURO--which will ultimately herald the next generation of clinical trials of cell therapy in PD, including those involving stem cells. In this chapter, we discuss what has been learned from previous studies of neural transplantation and go on to consider how relevant disease-modifying effects could be demonstrated in PD. We then go on to discuss how the design of future trials of transplantation-based therapies might be better conceived and executed.

Although a range of treatments is available for Parkinson's disease (PD), conventional therapies merely improve the symptoms of the disorder and are not considered to have any effect on underlying neurodegeneration. Neuronal loss continues inexorably and leads to increasing handicap and disability as the disease advances. A fundamental goal of PD research has been to develop drugs that delay or halt progression - so-called disease-modifying therapies (DMTs). Although this effect has been claimed for a number of different agents over the past decades - most recently rasagiline - these effects have not proved to be reproducible.The first part of this article reviews the results of the major neuroprotective trials conducted in PD and we argue that flaws in the design of these studies may account for their equivocal results. To establish whether a therapy has an effect on the prevention or postponement of disability, relevant endpoints must be identified for clinical trials. We go on to examine the results of natural history studies in PD, identified using a MEDLINE search with the appropriate MesH headings, can tell us about the evolution of the disorder, and how these insights can in turn be used to identify meaningful clinical endpoints for DMT trials. We frame our discussion by proposing two alternative models of PD progression and illustrate how the use of such models can inform the design of future DMT trials in PD, including the next generation of studies using novel interventional therapies.The conventional design of DMT trials in PD is flawed. Insights from natural history studies allow the identification of outcome measures which reflect true clinical progression - for example, the failure of postural reflexes - and must inform future research in this important area.

Background Previous studies have failed to agree on the risk factors for excessive daytime sleepiness in Parkinson9s disease and the relative contribution of each as the disease progresses. Methods We studied two community-based incident Parkinson9s disease cohorts. Cohort 1 (n=128) were newly-diagnosed patients and Cohort 2 were assessed at 3.5 years (n=118), 5 years (n=90) and 7 years (n=45) following diagnosis. Using Epworth Sleepiness Scale score as the outcome variable, multivariate linear regression was used to identify risk factors for excessive daytime sleepiness at each assessment. Results Epworth Sleepiness Scale score was significantly lower at diagnosis (Cohort 1) compared to 3.5, 5 and 7 years following diagnosis (Cohort 2). In Cohort 1, the proportion of patients with excessive daytime sleepiness (Epworth Sleepiness Scale score >10) was 20%. In Cohort 2, this rose to 49%, 53% and 44% at 3.5, 5 and 7 years respectively. In the early stages of Parkinson9s disease, a non-tremor dominant motor phenotype, dopamine agonist use and depression were associated with excessive daytime sleepiness, whereas later on, motor disability and impaired quality of life became the most significant factors. Conclusions This is the first study to map the temporal evolution of excessive daytime sleepiness and its risk factors in an incident Parkinson9s disease cohort. We found that hypersomnolence is present throughout the course of the disease and increases with disease progression. The link between non-tremor dominant motor phenotype and excessive daytime sleepiness, but lack of association with cognitive function, implicates brainstem rather than cortex as the principal site of underlying pathology. Dopamine agonists appear to play a contributory role.