amyloid-beta-peptides and Parkinson-Disease

Cerebral microbleeds (MBs) have been found in patients with cognitive decline. We aimed to examine whether MBs are associated with motor or cognitive decline in patients with Parkinson's disease (PD). We enrolled 135 PD patients and 34 healthy controls. All participants underwent brain MRI and plasma biomarker assays, including tau, Aβ42, Aβ40, and α-synuclein. PD with dementia (PDD) was operationally defined as Mini-Mental State Examination (MMSE) score < 26 and advanced motor stage was defined as Hoehn-Yahr stage ≥ 3 during "on" status. The association between MBs and disease severity was examined using multivariate logistic regression models. More lobar MBs were observed in PD patients than controls (20.7% vs. 3.3%, p = 0.031). PDD patients had more lobar MBs (33.3% vs. 15.6%, p = 0.034), more white matter hyperintensity (p = 0.021) and reduced hippocampal volume (p = 0.001) than PD with normal cognition. The presence of lobar MB (odds ratio = 2.83 [95% confidence interval 1.04-7.70], p = 0.042) and severe white matter hyperintensity (3.29 [1.21-8.96], p = 0.020) was independently associated with PDD after adjusting for vascular risk factors and other confounders. Furthermore, plasma Aβ40 levels were associated the MMSE score (p = 0.004) after adjusting for age and sex. Our findings demonstrated that lobar MBs, reduced hippocampal volume, and elevated plasma Aβ40 levels are associated with PDD.

Topics: Aged; Amyloid beta-Peptides; Biomarkers; Case-Control Studies; Cerebral Hemorrhage; Cognition Disorders; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parkinson Disease; Peptide Fragments; Severity of Illness Index

The positron emission tomography (PET) radioligand [

Topics: Aging; Alzheimer Disease; Amyloid beta-Peptides; Animals; Area Under Curve; Brain; Carbon Radioisotopes; Disease Models, Animal; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Tissue Proteins; Organ Specificity; Parkinson Disease; Peptide Fragments; Positron-Emission Tomography; Pyridines; Pyrrolidinones; Radiopharmaceuticals; Synaptic Vesicles; Synucleinopathies

The assembly of small disordered proteins into highly ordered amyloid fibrils in Alzheimer's and Parkinson's patients is closely associated with dementia and neurodegeneration. Understanding the process of amyloid formation is thus crucial in the development of effective treatments for these devastating neurodegenerative diseases. Recently, a tiny, highly conserved and disordered protein called SERF was discovered to modify amyloid formation in

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Kinetics; Parkinson Disease; Peptide Fragments; Protein Aggregates; Protein Binding; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

To examine the differential diagnostic significance of cerebrospinal fluid (CSF) biomarkers reflecting Alzheimer's disease-related amyloid β (Aβ) production and aggregation, cortical neuronal damage, tau pathology, damage to long myelinated axons and astrocyte activation, which hypothetically separates patients with idiopathic normal pressure hydrocephalus (iNPH) from patients with other neurodegenerative disorders.. The study included lumbar CSF samples from 82 patients with iNPH, 75 with vascular dementia, 70 with Parkinson's disease, 34 with multiple system atrophy, 34 with progressive supranuclear palsy, 15 with corticobasal degeneration, 50 with Alzheimer's disease, 19 with frontotemporal lobar degeneration and 54 healthy individuals (HIs). We analysed soluble amyloid precursor protein alpha (sAPPα) and beta (sAPPβ), Aβ species (Aβ38, Aβ40 and Aβ42), total tau (T-tau), phosphorylated tau, neurofilament light and monocyte chemoattractant protein 1 (MCP-1).. Patients with iNPH had lower concentrations of tau and APP-derived proteins in combination with elevated MCP-1 compared with HI and the non-iNPH disorders. T-tau, Aβ40 and MCP-1 together yielded an area under the curve of 0.86, differentiating iNPH from the other disorders. A prediction algorithm consisting of T-tau, Aβ40 and MCP-1 was designed as a diagnostic tool using CSF biomarkers.. The combination of the CSF biomarkers T-tau, Aβ40 and MCP-1 separates iNPH from cognitive and movement disorders with good diagnostic sensitivity and specificity. This may have important implications for diagnosis and clinical research on disease mechanisms for iNPH.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Biomarkers; Case-Control Studies; Chemokine CCL2; Dementia, Vascular; Diagnosis, Differential; Female; Frontotemporal Lobar Degeneration; Humans; Hydrocephalus, Normal Pressure; Male; Middle Aged; Multiple System Atrophy; Neurofilament Proteins; Parkinson Disease; Peptide Fragments; Phosphoproteins; Sensitivity and Specificity; Supranuclear Palsy, Progressive; tau Proteins

This prospective observational study investigates the role of CSF biomarkers in predicting progression of dopa-resistant gait impairments in Parkinson disease (PD) in the first 36 months from diagnosis.. Quantitative gait analysis was carried out longitudinally using an instrumented walkway (GAITRite) in 108 people with PD and 130 age-matched controls. A subgroup of 44 people with PD underwent lumbar puncture from which a battery of CSF biomarkers was measured: β-amyloid 1-42 and 1-40 (Aβ42 and Aβ40), total and phosphorylated tau protein (t-tau/p-tau. Low baseline CSF Aβ42, and to a lesser extend Aβ40, predicted decline in gait characteristics in the first 3 years following diagnosis, independently explaining up to 12% of progression of step time variability (single task) and step length variability (dual-task). Interestingly, these findings were independent of age and cognition.. These findings implicate underlying amyloid pathology in neural networks involved in locomotor control. Results suggest that disturbed Aβ metabolism may be a biomarker for dopa-resistant gait impairments in early PD. Our findings raise interesting questions regarding therapeutic interventions such as compounds or molecules aimed at reducing amyloid burden to mitigate gait disturbance in early PD and potentially falls risk. Finally, progression of discrete gait characteristics suggests they may have potential as clinical biomarkers of pathology and disease progression.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Antiparkinson Agents; Biomarkers; Biomechanical Phenomena; Disease Progression; Dopamine Agents; Female; Gait; Humans; Linear Models; Longitudinal Studies; Male; Parkinson Disease; Peptide Fragments; Phosphorylation; Prognosis; Prospective Studies; Severity of Illness Index; tau Proteins; Treatment Outcome

Alzheimer's disease (AD) is diagnosed based upon medical history, neuropsychiatric examination, cerebrospinal fluid analysis, extensive laboratory analyses and cerebral imaging. Diagnosis is time consuming and labour intensive. Parkinson's disease (PD) is mainly diagnosed on clinical grounds.. The primary aim of this study was to differentiate patients suffering from AD, PD and healthy controls by investigating exhaled air with the electronic nose technique. After demonstrating a difference between the three groups the secondary aim was the identification of specific substances responsible for the difference(s) using ion mobility spectroscopy. Thirdly we analysed whether amyloid beta (Aβ) in exhaled breath was causative for the observed differences between patients suffering from AD and healthy controls.. We employed novel pulmonary diagnostic tools (electronic nose device/ion-mobility spectrometry) for the identification of patients with neurodegenerative diseases. Specifically, we analysed breath pattern differences in exhaled air of patients with AD, those with PD and healthy controls using the electronic nose device (eNose). Using ion mobility spectrometry (IMS), we identified the compounds responsible for the observed differences in breath patterns. We applied ELISA technique to measure Aβ in exhaled breath condensates.. The eNose was able to differentiate between AD, PD and HC correctly. Using IMS, we identified markers that could be used to differentiate healthy controls from patients with AD and PD with an accuracy of 94%. In addition, patients suffering from PD were identified with sensitivity and specificity of 100%. Altogether, 3 AD patients out of 53 participants were misclassified. Although we found Aβ in exhaled breath condensate from both AD and healthy controls, no significant differences between groups were detected.. These data may open a new field in the diagnosis of neurodegenerative disease such as Alzheimer's disease and Parkinson's disease. Further research is required to evaluate the significance of these pulmonary findings with respect to the pathophysiology of neurodegenerative disorders.

Topics: Aged; Alzheimer Disease; Amyloid beta-Peptides; Animals; Biomarkers; Blotting, Western; Breath Tests; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lung; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Middle Aged; Parkinson Disease; Peptide Fragments; Reproducibility of Results; Sensitivity and Specificity; Spectrum Analysis

The accumulation of insoluble amyloid-beta (Aβ) peptides is associated with neurodegenerative disorders, such as Alzheimer's disease (AD). As essential tremor (ET) could involve neurodegenerative processes in the cerebellum, we quantified soluble and insoluble Aβ in cerebellar cortices from patients diagnosed with ET (n=9), compared to Controls (n=16) or individuals with Parkinson's disease (n=10). Although ante-mortem cognitive performance was not documented, all individuals included had the diagnosis of AD ruled out by a neuropathologist. ELISA-determined concentrations of insoluble Aβ42 in ET patients displayed a bimodal distribution, with a median 246-fold higher than in Controls (P<0.01, Kruskal-Wallis). Higher Aβ42 concentrations were measured in the parietal cortex of the same ET patients, compared to Controls (107-fold median increase, P<0.01, Kruskal-Wallis), but similar phosphorylated tau levels were detected. The rise in cerebellar insoluble Aβ42 concentrations is not associated to APP expression and processing or the ApoE4 status. However, Aβ42 levels in ET individuals were correlated with cerebellar insoluble phosphorylated tau (r(2)=0.71, P=0.005), unphosphorylated neurofilament heavy chain (NF-H; r(2)=0.50, P=0.030) and Lingo-1 (r(2)=0.73, P=0.007), indicative of a generalized neurodegenerative process involving the cerebellum. Our results suggest prevalent accumulations of insoluble Aβ42 in the cerebellum of ET, but not in age-matched PD. Whether this anomaly plays a role in ET symptoms warrants further investigations.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Apolipoprotein E4; Cerebellar Cortex; Essential Tremor; Female; Humans; Male; Membrane Proteins; Nerve Tissue Proteins; Neurofilament Proteins; Parietal Lobe; Parkinson Disease; Peptide Fragments; Phosphorylation; Purkinje Cells; tau Proteins; Temporal Lobe

Dementia with Lewy bodies (DLB) is difficult to differentiate from other neuro-degenerative diseases. Patients are often mistaken to suffer from Parkinson's disease (PD) or Alzheimer's disease (AD) because of the overlapping clinical appearances concerning cognition and movement.. We investigated the possibility for a valid differential diagnosis using cerebrospinal fluid (CSF) biomarkers.. In the context of a large retrospective study, we analyzed data of patients suffering from degenerative, ischemic, or inflammatory CNS (central nervous system) diseases and identified those with DLB (n = 34), PD (n = 37), and AD (n = 47) for further analyses.. We detected abnormalities in the CSF profiles of those patients with DLB while using a combination of decreased amyloid-β (Aβ)42 and increased tau levels. By stratification of data by disease severity, we observed a high sensitivity of this combination especially in the subgroup of patients with advanced stages, while the sensitivity in early forms was lower. In addition, with clinical deterioration, the abnormalities in the CSF profile became more pronounced.. We conclude that DLB can be distinguished from PD, in spite of both being synucleinopathies, by CSF profiles using neurodegenerative marker analysis. The pathophysiology of increased tau and decreased Aβ levels in those conditions has to be elucidated further, since both proteins are known to be involved in the pathogenesis of AD, but no clear explanation has been postulated for DLB yet.

Topics: Aged; Alzheimer Disease; Amyloid beta-Peptides; Analysis of Variance; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lewy Body Disease; Male; Parkinson Disease; Peptide Fragments; Retrospective Studies; tau Proteins

To describe the frequency of mild cognitive impairment (MCI) in Parkinson disease (PD) in a cohort of newly diagnosed incident PD cases and the associations with a panel of biomarkers.. Between June 2009 and December 2011, 219 subjects with PD and 99 age-matched controls participated in clinical and neuropsychological assessments as part of a longitudinal observational study. Consenting individuals underwent structural MRI, lumbar puncture, and genotyping for common variants of COMT, MAPT, SNCA, BuChE, EGF, and APOE. PD-MCI was defined with reference to the new Movement Disorder Society criteria.. The frequency of PD-MCI was 42.5% using level 2 criteria at 1.5 SDs below normative values. Memory impairment was the most common domain affected, with 15.1% impaired at 1.5 SDs. Depression scores were significantly higher in those with PD-MCI than the cognitively normal PD group. A significant correlation was found between visual Pattern Recognition Memory and cerebrospinal β-amyloid 1-42 levels (β standardized coefficient = 0.350; p = 0.008) after controlling for age and education in a linear regression model, with lower β-amyloid 1-42 and 1-40 levels observed in those with PD-MCI. Voxel-based morphometry did not reveal any areas of significant gray matter loss in participants with PD-MCI compared with controls, and no specific genotype was associated with PD-MCI at the 1.5-SD threshold.. In a large cohort of newly diagnosed PD participants, PD-MCI is common and significantly correlates with lower cerebrospinal β-amyloid 1-42 and 1-40 levels. Future longitudinal studies should enable us to determine those measures predictive of cognitive decline.

Topics: Aged; Aged, 80 and over; Amyloid beta-Peptides; Case-Control Studies; Cognitive Dysfunction; Female; Humans; Intermediate Filament Proteins; Male; Middle Aged; Neuropsychological Tests; Parkinson Disease; Peptide Fragments; Retrospective Studies; Severity of Illness Index; tau Proteins

ParkWest is a large Norwegian multicenter study of newly diagnosed drug-naïve subjects with Parkinson's disease (PD). Cognitively normal PD subjects (PDCN) and PD subjects with mild cognitive impairment (PDMCI) from this cohort have significant hippocampal atrophy and ventricular enlargement, compared to normal controls. Here, we aimed to investigate whether the same structural changes are associated with cerebrospinal fluid (CSF) levels of amyloid beta (Aβ)38 , Aβ40 , Aβ42 , total tau (t-tau), and phosphorylated tau (p-tau). We performed three-dimensional radial distance analyses of the hippocampi and lateral ventricles using the MRI data from ParkWest subjects who provided CSF at baseline. Our sample consisted of 73 PDCN and 18 PDMCI subjects. We found significant associations between levels of all three CSF Aβ analytes and t-tau and lateral ventricular enlargement in the pooled sample. In the PDCN sample, all three amyloid analytes showed significant associations with the radial distance of the occipital and frontal horns of the lateral ventricles. CSF Aβ38 and Aβ42 showed negative associations, with enlargement in occipital and frontal horns of the lateral ventricles in the pooled sample, and a negative association with the occipital horns in PDMCI. CSF Aβ levels in early PD correlate with ventricular enlargement, previously associated with PD dementia. Therefore, CSF and MRI markers may help identify PD patients at high risk for developing cognitive decline and dementia in the course of their illness. Contrary to Alzheimer's disease, we found no associations between CSF t-tau and p-tau and hippocampal atrophy.

Topics: Aged; Amyloid beta-Peptides; Apolipoproteins E; Female; Hippocampus; Humans; Imaging, Three-Dimensional; Lateral Ventricles; Magnetic Resonance Imaging; Male; Mental Status Schedule; Middle Aged; Parkinson Disease; Peptide Fragments; Regression Analysis; Statistics as Topic; Statistics, Nonparametric; tau Proteins

The well-established core biomarkers used to identify Alzheimer's disease (AD) overlap with other dementia disorders such as dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD). This study aimed to evaluate whether the cerebrospinal fluid (CSF) amyloid-β (Aβ)1-42/Aβ1-40 ratio, measured by a novel method, could improve the differential diagnosis of AD, DLB and PDD.. CSF levels of Aβ1-40 and Aβ1-42 in patients with PDD, DLB, AD, Parkinson's disease and controls were analyzed using an amplified luminescent proximity homogenous immunoassay along with conventional immunoassays.. The CSF Aβ1-42/Aβ1-40 ratio increased discrimination of AD from PDD and DLB compared with either of the two Aβ biomarkers individually.. The use of the Aβ1-42/Aβ1-40 ratio could improve the differentiation of AD from PDD and DLB.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Amyloid beta-Peptides; Antibodies; Area Under Curve; Biomarkers; Dementia; Diagnosis, Differential; Diagnostic and Statistical Manual of Mental Disorders; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoassay; Lewy Body Disease; Male; Middle Aged; Parkinson Disease; Peptide Fragments; Psychiatric Status Rating Scales

The clinical distinction between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) is sometimes difficult, particularly in mild cases. Although CSF markers such as amyloid β42 (Aβ42) and P-tau can distinguish between AD and normal controls, their ability to distinguish between AD and DLB is not adequate.. This study aims to investigate whether CSF markers, in particular levels of Aβ38, can differentiate between mild AD and DLB.. 85 individuals were included after standardised diagnostic procedures: 30 diagnosed as probable AD, 23 probable DLB, 20 probable Parkinson's disease dementia and 12 non-demented control subjects. CSF levels of Aβ38, Aβ40 and Aβ42 were determined using commercially available ultra-sensitive multi-array kit assay (MSD) for human Aβ peptides. Total tau (T-tau) and phosphorylated tau (P-tau) were analysed using ELISA (Innotest). In addition, combinations (Aβ42/Aβ38, Aβ42/Aβ40, Aβ42/P-tau and Aβ42/Aβ38/P-tau) were assessed.. Significant between group differences were found for all CSF measures, and all except Aβ40, Aβ42 and Aβ42/P-tau differed between AD and DLB. The Aβ42/Aβ38 ratio was the measure that best discriminated between AD and DLB (AUC 0.765; p<0.005), with a sensitivity of 78% and a specificity of 67%.. This study suggests that the level of Aβ38 can potentially contribute in the diagnostic distinction between AD and DLB when combined with Aβ42. Single measures had low diagnostic accuracy, suggesting that developing a panel of markers is the most promising strategy. Studies with independent and larger samples and a priori cut-offs are needed to test this hypothesis.

Topics: Aged; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cohort Studies; Diagnosis, Differential; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lewy Body Disease; Male; Neuropsychological Tests; Norway; Parkinson Disease; Peptide Fragments; Reproducibility of Results; ROC Curve; Sex Characteristics; Sweden; tau Proteins

There is clear evidence implicating oxidative stress in the pathology of many neurodegenerative diseases. Reactive oxygen species (ROS) are the primary mediators of oxidative stress, and hydrogen peroxide, a key ROS, is generated during aggregation of the amyloid proteins associated with some of these diseases. Hydrogen peroxide is catalytically converted to the aggressive hydroxyl radical in the presence of Fe(II) and Cu(I), which renders amyloidogenic proteins such as beta-amyloid and alpha-synuclein (implicated in Alzheimer's disease (AD) and Parkinson's disease (PD), respectively) vulnerable to self-inflicted hydroxyl radical attack. Here, we report some of the peptide-derived radicals, detected by electron spin resonance spectroscopy employing sodium 3,5-dibromo-4-nitrosobenzenesulfonate as a spin-trap, following hydroxyl radical attack on Abeta(1-40), alpha-synuclein and some other related peptides. Significantly, we found that sufficient hydrogen peroxide was self-generated during the early stages of aggregation of Abeta(1-40) to produce detectable peptidyl radicals, on addition of Fe(II). Our results support the hypothesis that oxidative damage to Abeta (and surrounding molecules) in the brain in AD could be due, at least in part, to the self-generation of ROS. A similar mechanism could operate in PD and some other "protein conformational" disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Benzenesulfonates; Electron Spin Resonance Spectroscopy; Ferrous Compounds; Humans; Hydroxyl Radical; Nitroso Compounds; Parkinson Disease; Peptide Fragments; Peptides; Reactive Oxygen Species; Recombinant Fusion Proteins

Convergent biochemical and genetic evidence suggests that the formation of alpha-synuclein (alpha-syn) protein deposits is an important and, probably, seminal step in the development of Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). It has been reported that transgenic animals overexpressing human alpha-syn develop lesions similar to those found in the brain in PD, together with a progressive loss of dopaminergic cells and associated abnormalities of motor function. Inhibiting and/or reversing alpha-syn self-aggregation could, therefore, provide a novel approach to treating the underlying cause of these diseases. We synthesized a library of overlapping 7-mer peptides spanning the entire alpha-syn sequence, and identified amino acid residues 64-100 of alpha-syn as the binding region responsible for its self-association. Modified short peptides containing alpha-syn amino acid sequences from part of this binding region (residues 69-72), named alpha-syn inhibitors (ASI), were found to interact with full-length alpha-syn and block its assembly into both early oligomers and mature amyloid-like fibrils. We also developed a cell-permeable inhibitor of alpha-syn aggregation (ASID), using the polyarginine peptide delivery system. This ASID peptide was able to inhibit the DNA damage induced by Fe(II) in neuronal cells transfected with alpha-syn(A53T), a familial PD-associated mutation. ASI peptides without this delivery system did not reverse levels of Fe(II)-induced DNA damage. Furthermore, the ASID peptide increased (P<0.0005) the number of cells stained positive for Bcl-2, while significantly (P<0.05) decreasing the percentage of cells stained positive for BAX. These short peptides could serve as lead compounds for the design of peptidomimetic drugs to treat PD and related disorders.

Topics: alpha-Synuclein; Amino Acid Motifs; Amino Acid Sequence; Amyloid; Amyloid beta-Peptides; Antiparkinson Agents; bcl-2-Associated X Protein; Cell Line, Tumor; DNA Damage; Drug Design; Drug Evaluation, Preclinical; Humans; Iron; Molecular Sequence Data; Nerve Tissue Proteins; Neuroblastoma; Parkinson Disease; Peptide Fragments; Peptide Library; Peptides; Protein Binding; Proto-Oncogene Proteins c-bcl-2; Recombinant Proteins; Synucleins