alpha-synuclein and Cerebral-Amyloid-Angiopathy

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder characterized by the deposition of amyloid-β protein (Aβ) within brain blood vessels that develops in elderly people and Alzheimer's disease (AD) patients. Therefore, the investigation of biomarkers able to differentiate CAA patients from AD patients and healthy controls (HC) is of great interest, in particular in peripheral fluids.. The current study aimed to detect the neurodegenerative disease (ND)-related protein (i.e., Aβ1-40, Aβ1-42, tau, and α-synuclein) levels in both red blood cells (RBCs) and plasma of CAA patients and HC, evaluating their role as putative peripheral biomarkers for CAA.. For this purpose, the proteins' concentration was quantified in RBCs and plasma by homemade immunoenzymatic assays in an exploratory cohort of 20 CAA patients and 20 HC.. The results highlighted a significant increase of Aβ1-40 and α-synuclein concentrations in both RBCs and plasma of CAA patients, while higher Aβ1-42 and t-tau levels were detected only in RBCs of CAA individuals compared to HC. Moreover, Aβ1-42/Aβ1-40 ratio increased in RBCs and decreased in plasma of CAA patients. The role of these proteins as candidate peripheral biomarkers easily measurable with a blood sample in CAA needs to be confirmed in larger studies.. In conclusion, we provide evidence concerning the possible use of blood biomarkers for contributing to CAA diagnosis and differentiation from other NDs.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cerebral Amyloid Angiopathy; Humans; Neurodegenerative Diseases; tau Proteins

Alzheimer's disease is a complex disease characterized by overlapping phenotypes with different neurodegenerative disorders. Oligomers are considered the most toxic species in amyloid pathologies. We examined human AD brain samples using an anti-oligomer antibody generated in our laboratory and detected potential hybrid oligomers composed of amyloid-β, prion protein, α-synuclein, and TDP-43 phosphorylated at serines 409 and 410. These data and in vitro results suggest that Aβ oligomer seeds act as a template for the aggregation of other proteins and generate an overlapping phenotype with other neuronal disorders. Furthermore, these results could explain why anti-amyloid-β therapy has been unsuccessful.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Cell Line, Tumor; Cerebral Amyloid Angiopathy; DNA-Binding Proteins; Female; Frontal Lobe; Humans; Imaging, Three-Dimensional; Male; Mice; Neuroblastoma; Neuroimaging; Peptide Fragments; Prions

To recognize relationship of protein related neurodegeneration abnormal aggregation in the aged brains with their cognitive and motor functions.. Brain tissues from the consecutive autopsy cases of the aged from January 2005 to December 2006 in PLA General Hospital were carried out for immunohistochemical staining with beta amyloid, tau, α-synuclein and ubiquitin antibodies. The consortium to establish a registry for Alzheimer's disease (CERAD) was used to semi-quantitatively analyze Aβ positive core plaques density and Braak staging for tau positive neurofibrillary tangles (NFTs) and α-synuclein positive Lewy bodies. In addition, Aβ positive cerebral amyloid angiopathy (CAA), neuritic plaques and various ubiquitin positive structures were also observed. The relationship of these protein abnormal depositions in the aged brains with cognitive and motor functions were analyzed.. In brain tissues of 16 consecutive autopsy cases of the aged from 78 to 95 years, there were 13 cases with Aβ positive core plaques, their density was 2 cases with sparse, 2 cases with moderate and 9 cases with frequent, respectively, according to CREAD.Eight cases with Aβ positive CAA were found, including 6 cases of mild CAA and 2 cases of severe CAA. There were 12 cases with tau positive NFTs, including 6 cases with Braak stageI-II, 4 cases with stage III-IV and 2 cases with stage V-VI. There were 5 cases with frequent Aβ core plaques, meanwhile existing numerous tau/ubiquitin positive neuritic plaques and Braak stage IV-VI of tau positive NFTs, all of them presented cognitive dysfunction. Among 4 other cases with frequent Aβ core plaques, only one case coexisted α-synuclein positive Lewy bodies showed moderate cognitive impairment, remaining 3 cases did not present cognitive dysfunction. There were 4 cases with α-synuclein positive Lewy bodies in the brainstem, and all of these cases presented parkinsonian motor dysfunction. 13 cases with ubiquitin positive structures were found.. Beta amyloid protein positive deposit in the aged brain is an important marker of normal brain aging and cognitive impairment; frequent Aβ core plaques in the neocortex plus Braak IV and above tau positive NFTs are closely related to cognitive dysfunction of Alzheimer's disease; α-synuclein positive Lewy bodies in the brainstem is one of the important pathological markers of parkinsonian motor disorders; ubiquitin deposition involves the development of some characteristic structures of several neurodegenerative diseases.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Autopsy; Brain; Brain Chemistry; Cerebral Amyloid Angiopathy; Humans; Neurofibrillary Tangles; Plaque, Amyloid; tau Proteins; Ubiquitin

Elevated plasma total homocysteine is associated with increased risk of dementia/Alzheimer's disease, but underlying pathophysiological mechanisms are not fully understood. This study investigated possible links between baseline homocysteine, and post-mortem neuropathological and magnetic resonance imaging findings up to 10 years later in the Vantaa 85+ population including people aged ≥85 years. Two hundred and sixty-five individuals had homocysteine and autopsy data, of which 103 had post-mortem brain magnetic resonance imaging scans. Methenamine silver staining was used for amyloid-β and modified Bielschowsky method for neurofibrillary tangles and neuritic plaques. Macroscopic infarcts were identified from cerebral hemispheres, brainstem and cerebellum slices. Standardized methods were used to determine microscopic infarcts, cerebral amyoloid angiopathy, and α-synuclein pathology. Magnetic resonance imaging was used for visual ratings of the degree of medial temporal lobe atrophy, and periventricular and deep white matter hyperintensities. Elevated baseline homocysteine was associated with increased neurofibrillary tangles count at the time of death: for the highest homocysteine quartile, odds ratio (95% confidence interval) was 2.60 (1.28-5.28). The association was observed particularly in people with dementia, in the presence of cerebral infarcts, and with longer time between the baseline homocysteine assessment and death. Also, elevated homocysteine tended to relate to amyloid-β accumulation, but this was seen only with longer baseline-death interval: odds ratio (95% confidence interval) was 2.52 (0.88-7.19) for the highest homocysteine quartile. On post-mortem magnetic resonance imaging, for the highest homocysteine quartile odds ratio (95% confidence interval) was 3.78 (1.12-12.79) for more severe medial temporal atrophy and 4.69 (1.14-19.33) for more severe periventricular white matter hyperintensities. All associations were independent of several potential confounders, including common vascular risk factors. No relationships between homocysteine and cerebral macro- or microinfarcts, cerebral amyoloid angiopathy or α-synuclein pathology were detected. These results suggest that elevated homocysteine in adults aged ≥85 years may contribute to increased Alzheimer-type pathology, particularly neurofibrillary tangles burden. This effect seems to be more pronounced in the presence of cerebrovascular pathology. Randomized controlled trials are needed t

Topics: Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Apolipoproteins E; Cerebral Amyloid Angiopathy; Cerebrovascular Disorders; Community Health Planning; Diagnosis; Female; Homocysteine; Humans; Magnetic Resonance Imaging; Male; Neurofibrillary Tangles; Plaque, Amyloid

A growing body of evidence demonstrates an association between vascular risk factors and Alzheimer's disease. This study investigated the frequency and severity of atherosclerotic plaques in the circle of Willis in Alzheimer's disease and multiple other neurodegenerative diseases. Semi-quantitative data from gross and microscopic neuropathological examinations in 1000 cases were analysed, including 410 with a primary diagnosis of Alzheimer's disease, 230 with synucleinopathies, 157 with TDP-43 proteinopathies, 144 with tauopathies and 59 with normal ageing. More than 77% of subjects with Alzheimer's disease had grossly apparent circle of Willis atherosclerosis, a percentage that was significantly higher than normal (47%), or other neurodegenerative diseases (43-67%). Age- and sex-adjusted atherosclerosis ratings were highly correlated with neuritic plaque, paired helical filaments tau neurofibrillary tangle and cerebral amyloid angiopathy ratings in the whole sample and within individual groups. We found no associations between atherosclerosis ratings and α-synuclein or TDP-43 lesion ratings. The association between age-adjusted circle of Willis atherosclerosis and Alzheimer's disease-type pathology was more robust for female subjects than male subjects. These results provide further confirmation and specificity that vascular disease and Alzheimer's disease are interrelated and suggest that common aetiologic or reciprocally synergistic pathophysiological mechanisms promote both vascular pathology and plaque and tangle pathology.

Topics: Aged; Aged, 80 and over; Aging; alpha-Synuclein; Alzheimer Disease; Analysis of Variance; Cerebral Amyloid Angiopathy; Chi-Square Distribution; Circle of Willis; Dementia; DNA-Binding Proteins; Female; Humans; Intracranial Arteriosclerosis; Male; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Retrospective Studies; Risk Factors

Dementia with Lewy Bodies (DLB) is a common neurodegenerative disorder of the aging population characterized by α-synuclein accumulation in cortical and subcortical regions. Although neuropathology in advanced age has been investigated in dementias such as Alzheimer Disease (AD), severity of the neuropathology in the oldest old with DLB remains uncharacterized. For this purpose we compared characteristics of DLB cases divided into three age groups 70-79, 80-89 and ≥ 90 years (oldest old). Neuropathological indicators and levels of synaptophysin were assessed and correlated with clinical measurements of cognition and dementia severity. These studies showed that frequency and severity of DLB was lower in 80-89 and ≥ 90 year cases compared to 70-79 year old group but cognitive impairment did not vary with age. The extent of AD neuropathology correlated with dementia severity only in the 70-79 year group, while synaptophysin immunoreactivity more strongly associated with dementia severity in the older age group in both DLB and AD. Taken together these results suggest that the oldest old with DLB might represent a distinct group.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Brain; Cerebral Amyloid Angiopathy; Cerebral Cortex; Female; Humans; Immunohistochemistry; Lewy Body Disease; Male; Neurites; Neurofibrillary Tangles; Neuropsychological Tests; Paraffin Embedding; Plaque, Amyloid; Presynaptic Terminals; Synaptophysin; Tissue Fixation

The non-amyloid beta component of Alzheimer's disease amyloid (NAC) is detected in cerebral amyloid angiopathy; and the precursor of NAC is now known to be identical to alpha-synuclein (alpha-S), a major component of Lewy bodies in Parkinson's disease. We studied if cerebral vascular cells express alpha-S. Immunohistochemical studies of human cerebral tissues from control and cerebral amyloid angiopathy patients revealed the expression of alpha-S in vascular endothelial and smooth muscle cells. Then we studied the expression of alpha-S in vitro using cultures of vascular cells. Cultures of human umbilical vein endothelial cells and umbilical artery smooth muscle cells were found to constitutively express alpha-S messenger RNA and protein. alpha-S is normally expressed in vascular cells and may play some physiological role in the vascular wall.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Autopsy; Blotting, Northern; Blotting, Western; Cell Culture Techniques; Cerebral Amyloid Angiopathy; Cerebral Arteries; Fluorescent Antibody Technique; Gene Expression Regulation; Humans; Hydrogen Peroxide; Immunohistochemistry; Middle Aged; Nerve Tissue Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synucleins; Time Factors