The validation of objective and easy-to-implement biomarkers that can monitor the effects of fast-acting drugs among Parkinson's disease (PD) patients would benefit antiparkinsonian drug... Show moreThe validation of objective and easy-to-implement biomarkers that can monitor the effects of fast-acting drugs among Parkinson's disease (PD) patients would benefit antiparkinsonian drug development. We developed composite biomarkers to detect levodopa/carbidopa effects and to estimate PD symptom severity. For this development, we trained machine learning algorithms to select the optimal combination of finger tapping task features to predict treatment effects and disease severity. Data were collected during a placebo-controlled, crossover study with 20 PD patients. The alternate index and middle finger tapping (IMFT), alternative index finger tapping (IFT), and thumb-index finger tapping (TIFT) tasks and the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) III were performed during treatment. We trained classification algorithms to select features consisting of the MDS-UPDRS III item scores; the individual IMFT, IFT, and TIFT; and all three tapping tasks collectively to classify treatment effects. Furthermore, we trained regression algorithms to estimate the MDS-UPDRS III total score using the tapping task features individually and collectively. The IFT composite biomarker had the best classification performance (83.50% accuracy, 93.95% precision) and outperformed the MDS-UPDRS III composite biomarker (75.75% accuracy, 73.93% precision). It also achieved the best performance when the MDS-UPDRS III total score was estimated (mean absolute error: 7.87, Pearson's correlation: 0.69). We demonstrated that the IFT composite biomarker outperformed the combined tapping tasks and the MDS-UPDRS III composite biomarkers in detecting treatment effects. This provides evidence for adopting the IFT composite biomarker for detecting antiparkinsonian treatment effect in clinical trials. & COPY; 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. Show less
Buijsen, R.A.M.; Hu, M.C.; Saez-Gonzalez, M.; Notopoulou, S.; Mina, E.; Koning, W.; ... ; Roon-Mom, W.M.C. van 2023
BackgroundSpinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by a polyglutamine expansion in the ataxin-1 protein resulting in neuropathology including mutant ataxin-1... Show moreBackgroundSpinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by a polyglutamine expansion in the ataxin-1 protein resulting in neuropathology including mutant ataxin-1 protein aggregation, aberrant neurodevelopment, and mitochondrial dysfunction. ObjectivesIdentify SCA1-relevant phenotypes in patient-specific fibroblasts and SCA1 induced pluripotent stem cells (iPSCs) neuronal cultures. MethodsSCA1 iPSCs were generated and differentiated into neuronal cultures. Protein aggregation and neuronal morphology were evaluated using fluorescent microscopy. Mitochondrial respiration was measured using the Seahorse Analyzer. The multi-electrode array (MEA) was used to identify network activity. Finally, gene expression changes were studied using RNA-seq to identify disease-specific mechanisms. ResultsBioenergetics deficits in patient-derived fibroblasts and SCA1 neuronal cultures showed altered oxygen consumption rate, suggesting involvement of mitochondrial dysfunction in SCA1. In SCA1 hiPSC-derived neuronal cells, nuclear and cytoplasmic aggregates were identified similar in localization as aggregates in SCA1 postmortem brain tissue. SCA1 hiPSC-derived neuronal cells showed reduced dendrite length and number of branching points while MEA recordings identified delayed development in network activity in SCA1 hiPSC-derived neuronal cells. Transcriptome analysis identified 1050 differentially expressed genes in SCA1 hiPSC-derived neuronal cells associated with synapse organization and neuron projection guidance, where a subgroup of 151 genes was highly associated with SCA1 phenotypes and linked to SCA1 relevant signaling pathways. ConclusionsPatient-derived cells recapitulate key pathological features of SCA1 pathogenesis providing a valuable tool for the identification of novel disease-specific processes. This model can be used for high throughput screenings to identify compounds, which may prevent or rescue neurodegeneration in this devastating disease. (c) 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. Show less
Heijer, J.M. den; Kruithof, A.C.; Moerland, M.; Walker, M.; Dudgeon, L.; Justman, C.; ... ; Lansbury, P. 2023
BackgroundLoss-of-function mutations in the GBA1 gene are one of the most common genetic risk factors for onset of Parkinson's disease and subsequent progression (GBA-PD). GBA1 encodes the... Show moreBackgroundLoss-of-function mutations in the GBA1 gene are one of the most common genetic risk factors for onset of Parkinson's disease and subsequent progression (GBA-PD). GBA1 encodes the lysosomal enzyme glucocerebrosidase (GCase), a promising target for a possible first disease-modifying therapy. LTI-291 is an allosteric activator of GCase, which increases the activity of normal and mutant forms of GCase.ObjectivesThis first-in-patient study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of 28 daily doses of LTI-291 in GBA-PD.MethodsThis was a randomized, double-blind, placebo-controlled trial in 40 GBA-PD participants. Twenty-eight consecutive daily doses of 10, 30, or 60 mg of LTI-291 or placebo were administered (n = 10 per treatment allocation). Glycosphingolipid (glucosylceramide and lactosylceramide) levels were measured in peripheral blood mononuclear cells (PBMCs), plasma, and cerebrospinal fluid (CSF), and a test battery of neurocognitive tasks, the Movement Disorder Society-Unified Parkinson's Disease Rating Scale and the Mini-Mental State Exam, were performed.ResultsLTI-291 was generally well tolerated, no deaths or treatment-related serious adverse events occurred, and no participants withdrew due to adverse events. Cmax, and AUC0–6 of LTI-291 increased in a dose-proportional manner, with free CSF concentrations equal to the free fraction in plasma. A treatment-related transient increase in intracellular glucosylceramide (GluCer) in PBMCs was measured.ConclusionThese first-in-patient studies demonstrated that LTI-291 was well tolerated when administered orally for 28 consecutive days to patients with GBA-PD. Plasma and CSF concentrations that are considered pharmacologically active were reached (ie, sufficient to at least double GCase activity). Intracellular GluCer elevations were detected. Clinical benefit will be assessed in a larger long-term trial in GBA-PD. Show less
Background: Leucine-rich repeat kinase 2 (LRRK2) inhibition is a promising therapeutic approach for the treatment of Parkinson's disease (PD).Objective: The aim of this study was to evaluate the... Show moreBackground: Leucine-rich repeat kinase 2 (LRRK2) inhibition is a promising therapeutic approach for the treatment of Parkinson's disease (PD).Objective: The aim of this study was to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of the potent, selective, CNS-penetrant LRRK2 inhibitor BIIB122 (DNL151) in healthy participants and patients with PD.Methods: Two randomized, double-blind, placebo-controlled studies were completed. The phase 1 study (DNLI-C-0001) evaluated single and multiple doses of BIIB122 for up to 28 days in healthy participants. The phase 1b study (DNLI-C-0003) evaluated BIIB122 for 28 days in patients with mild to moderate PD. The primary objectives were to investigate the safety, tolerability, and plasma pharmacokinetics of BIIB122. Pharmacodynamic outcomes included peripheral and central target inhibition and lysosomal pathway engagement biomarkers.Results: A total of 186/184 healthy participants (146/145 BIIB122, 40/39 placebo) and 36/36 patients (26/26 BIIB122, 10/10 placebo) were randomized/treated in the phase 1 and phase 1b studies, respectively. In both studies, BIIB122 was generally well tolerated; no serious adverse events were reported, and the majority of treatment-emergent adverse events were mild. BIIB122 cerebrospinal fluid/unbound plasma concentration ratio was similar to 1 (range, 0.7-1.8). Dose-dependent median reductions from baseline were observed in whole-blood phosphorylated serine 935 LRRK2 (<= 98%), peripheral blood mononuclear cell phosphorylated threonine 73 pRab10 (<= 93%), cerebrospinal fluid total LRRK2 (<= 50%), and urine bis (monoacylglycerol) phosphate (<= 74%).Conclusions: At generally safe and well-tolerated doses, BIIB122 achieved substantial peripheral LRRK2 kinase inhibition and modulation of lysosomal pathways downstream of LRRK2, with evidence of CNS distribution and target inhibition. These studies support continued investigation of LRRK2 inhibition with BIIB122 for the treatment of PD. (c) 2023 Denali Therapeutics Inc and The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. Show less
Background: alpha-Synuclein (alpha Syn) is believed to play a central role in Parkinson's disease (PD) neuropathology and is considered a target for disease modification. UB-312 is a synthetic... Show moreBackground: alpha-Synuclein (alpha Syn) is believed to play a central role in Parkinson's disease (PD) neuropathology and is considered a target for disease modification. UB-312 is a synthetic alpha Syn peptide conjugated to a T helper peptide and is expected to induce antibodies specifically against oligomeric and fibrillar alpha Syn, making UB-312 a potential immunotherapeutic for synucleopathies. Objective: To investigate the safety, tolerability, and immunogenicity of UB-312 vaccination in healthy participants and to determine a safe and immunologically optimal dose for the first-in-patient study. Methods: Fifty eligible healthy participants were enrolled in a 44-week, randomized, placebo-controlled, double-blind study. Participants in seven cohorts were randomized to three intramuscular UB-312 or placebo injections at weeks 1, 5, and 13 (doses ranging between 40 and 2000 mu g). Safety and tolerability were assessed by adverse events, clinical laboratory, vital signs, electrocardiograms, and neurological and physical examinations. Immunogenicity was assessed by measuring serum and cerebrospinal fluid (CSF) anti-aSyn antibody concentrations. Results: Twenty-three participants received all three vaccinations of UB-312. Most adverse events were mild, transient, and self-resolving. Common treatment-emergent adverse events included headache, nasopharyngitis, vaccination-site pain, lumbar puncture-site pain, and fatigue. UB-312 induced dose- and time-dependent antibody production. Antibodies were detectable in serum and CSF of all participants receiving the 300/300/300 mu g UB-312 dose regimen. The average CSF/serum ratio was 0.2%. Conclusions: UB-312 was generally safe, well tolerated, and induced anti-aSyn antibodies in serum and CSF of healthy participants. The 100 and 300 mu g doses are selected for further evaluation in participants with PD. (C) 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society Show less
Background: Inhalation of apomorphine could be a faster-acting and more user-friendly alternative to subcutaneous injection for treating off periods in Parkinson's disease (PD). Objective: The aim... Show moreBackground: Inhalation of apomorphine could be a faster-acting and more user-friendly alternative to subcutaneous injection for treating off periods in Parkinson's disease (PD). Objective: The aim of this study was to compare the safety and pharmacokinetics of inhaled apomorphine (AZ-009) with subcutaneous apomorphine (APO-go PEN) in healthy volunteers (HVs) and to examine the safety, pharmacokinetics, and efficacy of AZ-009 in patients with PD. Methods: In part A of this study, eight HVs received 1 mg AZ-009 and 2 mg subcutaneous apomorphine in a randomized crossover manner. In the subsequent single ascending dose parts in HVs (part B, n = 16) and patients with PD (part C, n = 25), participants were randomized to placebo or AZ-009 up to 4 mg. In patients, after medication withdrawal, Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III and on/off states were assessed predose and postdose. Results: AZ-009 was rapidly absorbed with peak plasma concentrations at 2 minutes, as compared to 30 minutes for subcutaneous apomorphine. Adverse events for AZ-009 were comparable to subcutaneous apomorphine, except for mild and transient throat irritation. Adverse events limited AZ-009 dose escalation in HVs to 3 mg. Patients tolerated up to 4 mg. In patients with PD, 2, 3, and 4 mg AZ-009 reduced mean Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III score (standard deviation) by 10.7 (13.6), 12.8 (7.9), and 10.3 (3.7) points, respectively, compared to 4.8 (4.9) after placebo at 10 minutes postdose. The percentage of patients achieving full on within 45 minutes postdose increased dose dependently: 0% (placebo), 17% (2 mg), 50% (3 mg), and 83% (4 mg). Conclusions: AZ-009 appears to be a rapid-acting and reasonably well-tolerated formulation for treating off periods. (c) 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society Show less
Huntington disease is an autosomal dominant inherited brain disorder that typically becomes manifest in adulthood. Juvenile-onset Huntington disease refers to approximately 5% of patients with... Show moreHuntington disease is an autosomal dominant inherited brain disorder that typically becomes manifest in adulthood. Juvenile-onset Huntington disease refers to approximately 5% of patients with symptom onset before the age of 21 years. The causal factor is a pathologically expanded CAG repeat in the Huntington gene. Age at onset is inversely correlated with CAG repeat length. Juvenile-onset patients have distinct symptoms and signs with more severe pathology of involved brain structures in comparison with disease onset in adulthood. The aim of this review is to compare clinical and pathological features in juvenile- and adult-onset Huntington disease and to explore which processes potentially contribute to the observed differences. A specific focus is placed on molecular mechanisms of mutant huntingtin in early neurodevelopment and the interaction of a neurodegenerative disease and postnatal brain maturation. The importance of a better understanding of pathophysiological differences between juvenile- and adult-onset Huntington disease lies in development and implementation of new therapeutic strategies. (c) 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society Show less
Geraedts, V.J.; Koch, M.; Kuiper, R.; Kefalas, M.; Bäck, T.H.W.; Hilten, J.J.; ... ; Tannemaat, M.R. 2021
Background Subthalamic deep brain stimulation (STN DBS) may relieve refractory motor complications in Parkinson's disease (PD) patients. Despite careful screening, it remains difficult to determine... Show moreBackground Subthalamic deep brain stimulation (STN DBS) may relieve refractory motor complications in Parkinson's disease (PD) patients. Despite careful screening, it remains difficult to determine severity of alpha-synucleinopathy involvement which influences the risk of postoperative complications including cognitive deterioration. Quantitative electroencephalography (qEEG) reflects cognitive dysfunction in PD and may provide biomarkers of postoperative cognitive decline.Objective To develop an automated machine learning model based on preoperative EEG data to predict cognitive deterioration 1 year after STN DBS.Methods Sixty DBS candidates were included; 42 patients had available preoperative EEGs to compute a fully automated machine learning model. Movement Disorder Society criteria classified patients as cognitively stable or deteriorated at 1-year follow-up. A total of 16,674 EEG-features were extracted per patient; a Boruta algorithm selected EEG-features to reflect representative neurophysiological signatures for each class. A random forest classifier with 10-fold cross-validation with Bayesian optimization provided class-differentiation.Results Tweny-five patients were classified as cognitively stable and 17 patients demonstrated cognitive decline. The model differentiated classes with a mean (SD) accuracy of 0.88 (0.05), with a positive predictive value of 91.4% (95% CI 82.9, 95.9) and negative predictive value of 85.0% (95% CI 81.9, 91.4). Predicted probabilities between classes were highly differential (hazard ratio 11.14 [95% CI 7.25, 17.12]); the risk of cognitive decline in patients with high probabilities of being prognosticated as cognitively stable (>0.5) was very limited.Conclusions Preoperative EEGs can predict cognitive deterioration after STN DBS with high accuracy. Cortical neurophysiological alterations may indicate future cognitive decline and can be used as biomarkers during the DBS screening. (c) 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society Show less
Background The composite Unified Huntington's Disease Rating Scale (cUHDRS) is a multidimensional measure of progression in Huntington's disease (HD) being used as a primary outcome in clinical... Show moreBackground The composite Unified Huntington's Disease Rating Scale (cUHDRS) is a multidimensional measure of progression in Huntington's disease (HD) being used as a primary outcome in clinical trials investigating potentially disease-modifying huntingtin-lowering therapies.Objective Evaluating volumetric and structural connectivity correlates of the cUHDRS.Methods One hundred and nineteen premanifest and 119 early-HD participants were included. Gray and white matter (WM) volumes were correlated with cUHDRS cross-sectionally and longitudinally using voxel-based morphometry. Correlations between baseline fractional anisotropy (FA); mean, radial, and axial diffusivity; and baseline cUHDRS were examined using tract-based spatial statistics.Results Worse performance in the cUHDRS over time correlated with longitudinal volume decreases in the occipito-parietal cortex and centrum semiovale, whereas lower baseline scores correlated with decreased volume in the basal ganglia and surrounding WM. Lower cUHDRS scores were also associated with reduced FA and increased diffusivity at baseline.Conclusion The cUHDRS correlates with imaging biomarkers and tracks atrophy progression in HD supporting its biological relevance. (c) 2021 International Parkinson and Movement Disorder Society Show less
Garcia-Sanz, P.; Aerts, J.M.F.G.; Moratalla, R. 2020
Parkinson's disease (PD) is a progressive neurodegenerative disease where dopaminergic neurons in the substantia nigra are lost, resulting in a decrease in striatal dopamine and, consequently,... Show moreParkinson's disease (PD) is a progressive neurodegenerative disease where dopaminergic neurons in the substantia nigra are lost, resulting in a decrease in striatal dopamine and, consequently, motor control. Dopaminergic degeneration is associated with the appearance of Lewy bodies, which contain membrane structures and proteins, including alpha-synuclein (alpha-Syn), in surviving neurons. PD displays a multifactorial pathology and develops from interactions between multiple elements, such as age, environmental conditions, and genetics. Mutations in the GBA1 gene represent one of the major genetic risk factors for PD. This gene encodes an essential lysosomal enzyme called beta-glucocerebrosidase (GCase), which is responsible for degrading the glycolipid glucocerebroside into glucose and ceramide. GCase can generate glucosylated cholesterol via transglucosylation and can also degrade the sterol glucoside. Although the molecular mechanisms that predispose an individual to neurodegeneration remain unknown, the role of cholesterol in PD pathology deserves consideration. Disturbed cellular cholesterol metabolism, as reflected by accumulation of lysosomal cholesterol in GBA1-associated PD cellular models, could contribute to changes in lipid rafts, which are necessary for synaptic localization and vesicle cycling and modulation of synaptic integrity. alpha-Syn has been implicated in the regulation of neuronal cholesterol, and cholesterol facilitates interactions between alpha-Syn oligomers. In this review, we integrate the results of previous studies and describe the cholesterol landscape in cellular homeostasis and neuronal function. We discuss its implication in alpha-Syn and Lewy body pathophysiological mechanisms underlying PD, focusing on the role of GCase and cholesterol. (c) 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society. Show less
Heuvel, L. van den; Evers, L.; Meinders, M.; Post, B.; Stiggelbout, A.; Heskes, T.; ... ; Krijthe, J. 2020
Background Both patients and physicians may choose to delay initiation of dopamine replacement therapy in Parkinson's disease (PD) for various reasons. We used observational data to estimate the... Show moreBackground Both patients and physicians may choose to delay initiation of dopamine replacement therapy in Parkinson's disease (PD) for various reasons. We used observational data to estimate the effect of earlier treatment in PD. Observational data offer a valuable source of evidence, complementary to controlled trials.Method We studied the Parkinson's Progression Markers Initiative cohort of patients with de novo PD to estimate the effects of duration of PD treatment during the first 2 years of follow-up, exploiting natural interindividual variation in the time to start first treatment. We estimated the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III (primary outcome) and several functionally relevant outcomes at 2, 3, and 4 years after baseline. To adjust for time-varying confounding, we used marginal structural models with inverse probability of treatment weighting and the parametric g-formula.Results We included 302 patients from the Parkinson's Progression Markers Initiative cohort. There was a small improvement in MDS-UPDRS Part III scores after 2 years of follow-up for patients who started treatment earlier, and similar, but nonstatistically significant, differences in subsequent years. We found no statistically significant differences in most secondary outcomes, including the presence of motor fluctuations, nonmotor symptoms, MDS-UPDRS Part II scores, and the Schwab and England Activities of Daily Living Scale.Conclusion Earlier treatment initiation does not lead to worse MDS-UPDRS motor scores and may offer small improvements. These findings, based on observational data, are in line with earlier findings from clinical trials. Observational data, when combined with appropriate causal methods, are a valuable source of additional evidence to support real-world clinical decisions. (c) 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society Show less
Iwaki, H.; Blauwendraat, C.; Leonard, H.L.; Makarious, M.B.; Kim, J.J.; Liu, G.Q.; ... ; Nalls, M.A. 2020
Background Previous studies reported various symptoms of Parkinson's disease (PD) associated with sex. Some were conflicting or confirmed in only one study. Objectives We examined sex associations... Show moreBackground Previous studies reported various symptoms of Parkinson's disease (PD) associated with sex. Some were conflicting or confirmed in only one study. Objectives We examined sex associations to PD phenotypes cross-sectionally and longitudinally in large-scale data. Methods We tested 40 clinical phenotypes, using longitudinal, clinic-based patient cohorts, consisting of 5946 patients, with a median follow-up of 3.1 years. For continuous outcomes, we used linear regressions at baseline to test sex-associated differences in presentation, and linear mixed-effects models to test sex-associated differences in progression. For binomial outcomes, we used logistic regression models at baseline and Cox regression models for survival analyses. We adjusted for age, disease duration, and medication use. In the secondary analyses, data from 17 719 PD patients and 7588 non-PD participants from an online-only, self-assessment PD cohort were cross-sectionally evaluated to determine whether the sex-associated differences identified in the primary analyses were consistent and unique to PD. Results Female PD patients had a higher risk of developing dyskinesia early during the follow-up period, with a slower progression in activities of daily living difficulties, and a lower risk of developing cognitive impairments compared with male patients. The findings in the longitudinal, clinic-based cohorts were mostly consistent with the results of the online-only cohort. Conclusions We observed sex-associated contributions to PD heterogeneity. These results highlight the necessity of future research to determine the underlying mechanisms and importance of personalized clinical management. (c) 2020 International Parkinson and Movement Disorder Society Show less
Background The most common genetic risk factor for Parkinson's disease known is a damaging variant in theGBA1gene. The entireGBA1gene has rarely been studied in a large cohort from a single... Show moreBackground The most common genetic risk factor for Parkinson's disease known is a damaging variant in theGBA1gene. The entireGBA1gene has rarely been studied in a large cohort from a single population. The objective of this study was to assess the entireGBA1gene in Parkinson's disease from a single large population. Methods TheGBA1gene was assessed in 3402 Dutch Parkinson's disease patients using next-generation sequencing. Frequencies were compared with Dutch controls (n = 655). Family history of Parkinson's disease was compared in carriers and noncarriers. Results Fifteen percent of patients had aGBA1nonsynonymous variant (including missense, frameshift, and recombinant alleles), compared with 6.4% of controls (OR, 2.6;P < 0.001). Eighteen novel variants were detected. Variants previously associated with Gaucher's disease were identified in 5.0% of patients compared with 1.5% of controls (OR, 3.4;P < 0.001). The rarely reported complex allele p.D140H + p.E326K appears to likely be a Dutch founder variant, found in 2.4% of patients and 0.9% of controls (OR, 2.7;P= 0.012). The number of first-degree relatives (excluding children) with Parkinson's disease was higher in p.D140H + p.E326K carriers (5.6%, 21 of 376) compared with p.E326K carriers (2.9%, 29 of 1014); OR, 2.0;P= 0.022, suggestive of a dose effect for differentGBA1variants. Conclusions Dutch Parkinson's disease patients display one of the largest frequencies ofGBA1variants reported so far, consisting in large part of the mild p.E326K variant and the more severe Dutch p.D140H + p.E326K founder allele. (c) 2020 International Parkinson and Movement Disorder Society Show less
Background Changes in phosphodiesterase 10A enzyme levels may be a suitable biomarker of disease progression in Huntington's disease. Objectives To evaluate phosphodiesterase 10A PET imaging as a... Show moreBackground Changes in phosphodiesterase 10A enzyme levels may be a suitable biomarker of disease progression in Huntington's disease. Objectives To evaluate phosphodiesterase 10A PET imaging as a biomarker of HD progression using the radioligand, [F-18]MNI-659. Methods The cross-sectional study (NCT02061722) included 45 Huntington's disease gene-expansion carriers stratified into four disease stages (early and late premanifest and Huntington's disease stages 1 and 2) and 45 age- and sex-matched healthy controls. The primary analysis compared striatal and pallidal phosphodiesterase 10A availability between Huntington's disease gene-expansion carriers and healthy controls as assessed by [F-18]MNI-659 binding. We assessed changes in phosphodiesterase 10A expression using several PET methodologies and compared with previously proposed measures of Huntington's disease progression (PET imaging of D-2/3 receptors and anatomical volume loss on MRI). The longitudinal follow-up study (NCT02956148) continued evaluation of phosphodiesterase 10A availability in 35 Huntington's disease gene-expansion carriers at a mean of 18 months from baseline of the cross-sectional study. Results Primary analyses revealed that phosphodiesterase 10A availability in caudate, putamen, and globus pallidus was significantly lower in Huntington's disease gene-expansion carriers versus healthy controls across all stages. Striatal and pallidal phosphodiesterase 10A availability progressively declined in the premanifest stages and appeared to plateau between stages 1 and 2. The percentage decline of phosphodiesterase 10A availability measured cross-sectionally between Huntington's disease gene-expansion carriers and healthy controls was greater than that demonstrated by D-2/3 receptor availability or volumetric changes. Annualized rates of phosphodiesterase 10A change showed a statistically significant decline between the cross-sectional study and follow-up. Conclusions [F-18]MNI-659 PET imaging is a biologically plausible biomarker of Huntington's disease progression that is more sensitive than the dopamine-receptor and volumetric methods currently used. (c) 2020 International Parkinson and Movement Disorder Society Show less
