Amyloid beta (Aβ or Abeta) is a peptide of 36–43 amino acids that is processed from the Amyloid precursor protein. While best known as a component of amyloid plaques in association with Alzheimer's disease, evidence has been found that Aβ is a highly multifunctional peptide with significant non-pathological activity.[1] Aβ is the main component of deposits found in the brains of patients with Alzheimer's disease
Beta Amyloid Peptide: Research Paper : Syringin Prevents Aβ 25-35-Induced Neurotoxicity in SK-N-SH and SK-N-BE Cells by Modulating miR-124-3p/BID Pathway
Beta Amyloid Peptide: Research Paper : Composite UHDRS Correlates With Progression of Imaging Biomarkers in Huntington's Disease
Composite UHDRS Correlates With Progression of Imaging Biomarkers in Huntington's Disease
Abstract
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 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. © 2021 International Parkinson and Movement Disorder Society.
Keywords: Huntington's disease; composite Unified Huntington's Disease Rating Scale; diffusion tensor imaging; voxel-based morphometry; clinical trials; longitudinal.
Beta Amyloid Peptide: Research Paper : 18F-flortaucipir PET to autopsy comparisons in Alzheimer's disease and other neurodegenerative diseases
18F-flortaucipir PET to autopsy comparisons in Alzheimer's disease and other neurodegenerative diseases
Abstract
Few studies have evaluated the relationship between in vivo18F-flortaucipir PET and post-mortem pathology. We sought to compare antemortem 18F-flortaucipir PET to neuropathology in a consecutive series of patients with a broad spectrum of neurodegenerative conditions. Twenty patients were included [mean age at PET 61 years (range 34-76); eight female; median PET-to-autopsy interval of 30 months (range 4-59 months)]. Eight patients had primary Alzheimer's disease pathology, nine had non-Alzheimer tauopathies (progressive supranuclear palsy, corticobasal degeneration, argyrophilic grain disease, and frontotemporal lobar degeneration with MAPT mutations), and three had non-tau frontotemporal lobar degeneration. Using an inferior cerebellar grey matter reference, 80-100-min 18F-flortaucipir PET standardized uptake value ratio (SUVR) images were created. Mean SUVRs were calculated for progressive supranuclear palsy, corticobasal degeneration, and neurofibrillary tangle Braak stage regions of interest, and these values were compared to SUVRs derived from young, non-autopsy, cognitively normal controls used as a standard for tau negativity. W-score maps were generated to highlight areas of increased tracer retention compared to cognitively normal controls, adjusting for age as a covariate. Autopsies were performed blinded to PET results. There was excellent correspondence between areas of 18F-flortaucipir retention, on both SUVR images and W-score maps, and neurofibrillary tangle distribution in patients with primary Alzheimer's disease neuropathology. Patients with non-Alzheimer tauopathies and non-tau frontotemporal lobar degeneration showed a range of tracer retention that was less than Alzheimer's disease, though higher than age-matched, cognitively normal controls. Overall, binding across both tau-positive and tau-negative non-Alzheimer disorders did not reliably correspond with post-mortem tau pathology. 18F-flortaucipir SUVRs in subcortical regions were higher in autopsy-confirmed progressive supranuclear palsy and corticobasal degeneration than in controls, but were similar to values measured in Alzheimer's disease and tau-negative neurodegenerative pathologies. Quantification of 18F-flortaucipir SUVR images at Braak stage regions of interest reliably detected advanced Alzheimer's (Braak VI) pathology. However, patients with earlier Braak stages (Braak I-IV) did not show elevated tracer uptake in these regions compared to young, tau-negative controls. In summary, PET-to-autopsy comparisons confirm that 18F-flortaucipir PET is a reliable biomarker of advanced Braak tau pathology in Alzheimer's disease. The tracer cannot reliably differentiate non-Alzheimer tauopathies and may not detect early Braak stages of neurofibrillary tangle pathology.
Keywords: Alzheimer's disease; neurofibrillary tangle; neuropathology; positron emission tomography; tau.
Beta Amyloid Peptide: Research Paper : GABA and glutamate deficits from frontotemporal lobar degeneration are associated with disinhibition
GABA and glutamate deficits from frontotemporal lobar degeneration are associated with disinhibition
Abstract
Behavioural disinhibition is a common feature of the syndromes associated with frontotemporal lobar degeneration (FTLD). It is associated with high morbidity and lacks proven symptomatic treatments. A potential therapeutic strategy is to correct the neurotransmitter deficits associated with FTLD, thereby improving behaviour. Reductions in the neurotransmitters glutamate and GABA correlate with impulsive behaviour in several neuropsychiatric diseases and there is post-mortem evidence of their deficit in FTLD. Here, we tested the hypothesis that prefrontal glutamate and GABA levels are reduced by FTLD in vivo, and that their deficit is associated with impaired response inhibition. Thirty-three participants with a syndrome associated with FTLD (15 patients with behavioural variant frontotemporal dementia and 18 with progressive supranuclear palsy, including both Richardson's syndrome and progressive supranuclear palsy-frontal subtypes) and 20 healthy control subjects were included. Participants undertook ultra-high field (7 T) magnetic resonance spectroscopy and a stop-signal task of response inhibition. We measured glutamate and GABA levels using semi-LASER magnetic resonance spectroscopy in the right inferior frontal gyrus, because of its strong association with response inhibition, and in the primary visual cortex, as a control region. The stop-signal reaction time was calculated using an ex-Gaussian Bayesian model. Participants with frontotemporal dementia and progressive supranuclear palsy had impaired response inhibition, with longer stop-signal reaction times compared with controls. GABA concentration was reduced in patients versus controls in the right inferior frontal gyrus, but not the occipital lobe. There was no group-wise difference in partial volume corrected glutamate concentration between patients and controls. Both GABA and glutamate concentrations in the inferior frontal gyrus correlated inversely with stop-signal reaction time, indicating greater impulsivity in proportion to the loss of each neurotransmitter. We conclude that the glutamatergic and GABAergic deficits in the frontal lobe are potential targets for symptomatic drug treatment of frontotemporal dementia and progressive supranuclear palsy.
Keywords: GABA; frontotemporal dementia; glutamate; impulsivity; progressive supranuclear palsy.
Beta Amyloid Peptide: Research Paper : Evidence of A Negative Feedback Network Between TDP-43 and miRNAs Dependent on TDP-43 Nuclear Localization
Evidence of A Negative Feedback Network Between TDP-43 and miRNAs Dependent on TDP-43 Nuclear Localization
Abstract
TAR DNA-binding protein 43 (TDP-43) is a DNA/RNA-binding protein that is integral to RNA processing. Among these functions is a critical role in microRNA (miRNA) biogenesis through interactions with the DROSHA and DICER complexes. It has been previously shown that there is a general reduction in miRNA levels within the spinal cord and spinal motor neurons of amyotrophic lateral sclerosis (ALS) patients. In addition, the most common pathological feature of ALS is re-distribution of TDP-43 from the nucleus to the cytoplasm where it forms cytoplasmic inclusions. Among miRNAs dysregulated in ALS, several are known to regulate TDP-43 expression. In this study, we demonstrate that TDP-43 is in a regulatory negative feedback network with miR-181c-5p and miR-27b-3p that is dependent on its nuclear localization within HEK293T cells. Further, we show that cellular stress which induces a redistribution of TDP-43 from the nucleus to the cytoplasm correlates with the reduced production of miR-27b-3p and miR-181c-5p. This suggests that reduced nuclear TDP-43 disrupts a negative feedback network between itself and miRNAs. These findings provide a further understanding of altered miRNA biogenesis as a key pathogenic process in ALS.
Keywords: ALS; TDP-43; cell stress; miR-181c; miR-27b; microRNAs.
Beta Amyloid Peptide: Research Paper : Cortical hypometabolism associated with cognitive impairment of multiple system atrophy
Cortical hypometabolism associated with cognitive impairment of multiple system atrophy
Abstract
Introduction: Cognitive impairment is not uncommon in patients with multiple system atrophy (MSA). This study investigated the cortical metabolic changes of MSA and the cortical structure associated with cognitive impairment.
Methods: The study included probable/definite MSA patients who underwent fluorodeoxyglucose positron emission tomography and cognitive evaluation based on mini-mental status examination (MMSE). Cerebral metabolism of the entire MSA patients (n = 88) was compared with healthy controls (n = 19) by voxel-wise statistical parametric mapping. Eight brain regions of interest (ROIs) were selected accordingly: the dorsolateral prefrontal, medial superior frontal, insular, posterior parietal, precuneus, lateral temporal, medial temporal, and posterior cingulate regions. Using validated population-based norms, MSA patients were divided by MMSE z-scores into MSA with cognitive dysfunction (MSA-D, n = 30) and without cognitive dysfunction (MSA-ND, n = 58). Regional metabolism of the selected ROIs was compared between the MSA-D and MSA-ND groups by logistic regression models. Correlations between the regional metabolism of the selected ROIs and MMSE z-scores were analyzed with a linear regression model.
Results: Voxel-wise analysis showed hypometabolism in the frontal, temporal, parietal, and limbic areas in MSA patients than in controls. ROI-based comparisons showed that metabolism in the posterior cingulate (P = 0.006) and medial temporal (P = 0.039) regions was significantly lower in the MSA-D than in the MSA-ND group. The degree of posterior cingulate metabolism correlated significantly with MMSE z-score (P = 0.023).
Conclusions: MSA shows fronto-temporo-parietal cortical involvement. Hypometabolism of the limbic regions is associated with cognitive impairment in MSA.
Keywords: Cognitive impairment; Fluorodeoxyglucose positron emission tomography imaging; Multiple system atrophy.
Beta Amyloid Peptide: Research Paper : Association of blood-based transcriptional risk scores with biomarkers for Alzheimer disease
Association of blood-based transcriptional risk scores with biomarkers for Alzheimer disease
Abstract
Objective: To determine whether transcriptional risk scores (TRSs), a summation of polarized expression levels of functional genes, reflect the risk of Alzheimer disease (AD).
Methods: Blood transcriptome data were from Caucasian participants, which included AD, mild cognitive impairment, and cognitively normal controls (CN) in the Alzheimer's Disease Neuroimaging Initiative (ADNI, n = 661) and AddNeuroMed (n = 674) cohorts. To calculate TRSs, we selected functional genes that were expressed under the control of the AD risk loci and were identified as being responsible for AD by using Bayesian colocalization and mendelian randomization methods. Regression was used to investigate the association of the TRS with diagnosis (AD vs CN) and MRI biomarkers (entorhinal thickness and hippocampal volume). Regression was also used to evaluate whether expression of each functional gene was associated with AD diagnosis.
Results: The TRS was significantly associated with AD diagnosis, hippocampal volume, and entorhinal cortical thickness in the ADNI. The association of the TRS with AD diagnosis and entorhinal cortical thickness was also replicated in AddNeuroMed. Among functional genes identified to calculate the TRS, CD33 and PILRA were significantly upregulated, and TRAPPC6A was significantly downregulated in patients with AD compared with CN, all of which were identified in the ADNI and replicated in AddNeuroMed.
Conclusions: The blood-based TRS is significantly associated with AD diagnosis and neuroimaging biomarkers. In blood, CD33 and PILRA were known to be associated with uptake of β-amyloid and herpes simplex virus 1 infection, respectively, both of which may play a role in the pathogenesis of AD.
Classification of evidence: The study is rated Class III because of the case control design and the risk of spectrum bias.
Beta Amyloid Peptide: Research Paper : Mitochondria and cellular redox state on the route from ageing to Alzheimer's disease
Mitochondria and cellular redox state on the route from ageing to Alzheimer's disease
Abstract
Several theories have been postulated, trying to explain why and how living organisms age. Despite some controversies and still huge open questions, a growing body of evidence suggest alterations of mitochondrial functionality and redox-homeostasis occur during the ageing process. Oxidative damage and mitochondrial dysfunction do not represent the cause of ageing per se but they have to be analyzed within the complexity of those series of processes occurring during lifespan. The establishment of a crosstalk among them is a shared common feature of many chronic age-related diseases, including neurodegenerative disorders, for which ageing is a major risk factor. The challenge is to understand when and how the interplay between these two systems move towards from normal ageing process to a pathological phenotype. Here in this review, we discuss the crosstalk between mitochondria and cytosolic-ROS. Furthermore, through a visual data mining approach, we attempt to describe the dynamic interplay between mitochondria and cellular redox state on the route from ageing to an AD phenotype.
Keywords: Ageing; Alzheimer's disease; Mitochondrion; Redox homeostasis; Threshold.
Beta Amyloid Peptide: Research Paper : Dual prophylactic/therapeutic potential of date seed, and nigella and olive oils-based nutraceutical formulation in rats with experimentally-induced Alzheimer's disease: A mechanistic insight
Dual prophylactic/therapeutic potential of date seed, and nigella and olive oils-based nutraceutical formulation in rats with experimentally-induced Alzheimer's disease: A mechanistic insight
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder with a multifactorial etiology and significantly increasing incidence during the last decade. Hence, developing an effective therapy is crucial for public health. The current study aimed to examine the dual prophylactic/therapeutic potential of a nutraceutical formula based on aqueous extract of roasted date seeds, and nigella and virgin-olive oils against experimentally-induced Alzheimer's disease in rats. Alzheimer's disease-like pathology was induced in male Wistar rats using oral CuSO4 (200 mg/Kg/day for two months). The nutraceutical formula was given orally to experimental animals (10 mL/kg/d) for 14 days before (as prophylaxis) and after Alzheimer's disease induction and its therapeutic effect in both cases is tested in comparison to donepezil (0.5 mg/kg/d). The nutraceutical formula was found to ameliorate the CuSO4-induced neuronal damage and regenerate the affected hippocampus tissue and significantly improvemed in learning ability. The formula was also effective in decreasing brain amyloid-β, tau protein, TNF-α level, iNOS level in hippocampus, oxidative stress level, and inhibiting acetylcholinesterase activity and expression in brain and hippocampus, respectively. Further, an increase in GSH levels, activities of SOD, and GST and levels of hippocampus ADAM 17 and brain phospholipids was observed. In conclusion, the studied nutraceutical formula is proved to be effective in ameliorating Alzheimer's neurodegenerative progression with added-prophylactic potential.
Keywords: ADAM 17; Alzheimer's disease; Amyloid β; Neurodegeneration; Oxidative stress; TNF-α; Tau protein.
Beta Amyloid Peptide: Research Paper : Randomized trial of a patient empowerment and cognitive training program for older people with diabetes mellitus and cognitive impairment
Randomized trial of a patient empowerment and cognitive training program for older people with diabetes mellitus and cognitive impairment
Abstract
Aim: To evaluate the effectiveness of a combined patient empowerment program (PEP) and cognitive training (CT) program on improving glycemic control among older subjects with diabetes and cognitive impairment.
Methods: A prospective single blinded, randomized controlled study was carried out in 139 older patients with diabetes aged ≥65 years with memory complaints and recent glycosylated hemoglobin level of 7-9%. They were randomly assigned to either undergo once-weekly PEP combined with CT for 10 weeks (intervention group, N = 73) or receive no intervention (control group, N = 66). All participants were followed up at months 4 and 12 to examine the immediate and long-term effects on glycemic control, cognition, mood and compliance to drug and diabetes self-management.
Results: The intervention did not significantly reduce glycosylated hemoglobin. The intervention group showed significant progressive improvement in memory over 1 year and executive function improved significantly at month 12. There was no significant change in diabetes self-management activities with the intervention.
Conclusions: Combination of PEP and CT did not improve glycemic control or self-care activities in older patients with diabetes and memory complaints but was effective in improving cognitive function in the longer term. Geriatr Gerontol Int 2020; 20: 1164-1170.
Keywords: cognitive impairment; cognitive training; diabetes mellitus; patient empowerment; self-management.
The secret of Eta Black by Ananya Sharma
The secret of Eta Black by Ananya Sharma A man sitting behind the bars named Eta black has no clue what is happening with him. He was searc...
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Amyloid Beta Derived Diffusible Ligand: Beta Amyloid Ligands: Research Papers Sim PL, Heese K. Ligand-Dependent Activation of the Chi...
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Beta Amyloid 25-35 : Abeta 25-35 :Amyloid Beta Peptide:25-35 : Beta Amyloid Peptides 25-35 : Research Paper of Abeta Peptide 25-35 Beta amyl...
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The amyloid hypothesis is initially compelling because the gene for the amyloid beta precursor APP is located on chromosome 21 , and pati...
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Amyloid Cascade in Alzheimer’s Disease Review Article Shankar P S Address for correspondence: P S Shankar, Emeritus Professor ...
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Subscribe to Amyloid et.al. by Email Phf1 Tau Antibody Guerrero R, Navarro P, Gallego E, Garcia-Cabrero AM, Avila J, Sanchez ...
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Beta Amyloid Antibody Lambracht-Washington D, Qu BX, Fu M, Eagar TN, Stüve O, Rosenberg RN. DNA beta-amyloid(1-42) trimer immunization f...
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Amyloid Research Fund: Amyloid Research Grants: Funding on Amyloid Reserach Program: Everyday Technologies for Alzheimer...
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Alzheimer’s Research References/Papers: September 2009 4th Week’s: Alzheimer’s Research References/Papers Elsinghorst PW, Härtig W, Goldhamm...
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Subscribe to Amyloid et.al. by Email Tau Antibody at8 Ichihara K, Uchihara T, Nakamura A, Suzuki Y, Mizutani T. Selective d...
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Gavett BE, Stern RA, McKee AC. Chronic traumatic encephalopathy: a potential late effect of sport-related concussive and subconcussive head ...