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Neurodegenerative pathologies such as Alzheimer disease neuropathologic change (ADNC), Lewy body disease (LBD), limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC), and cerebrovascular disease (CVD) frequently coexist, but little is known about the exact contribution of each pathology to cognitive decline and dementia in subjects with mixed pathologies. We explored the relative cognitive impact of concurrent common and rare neurodegenerative pathologies employing multivariate logistic regression analysis adjusted for age, gender, and level of education. We analyzed a cohort of 6,262 subjects from the National Alzheimer’s Coordinating Center database, ranging from 0 to 6 comorbid neuropathologic findings per individual, where 95.7% of individuals had at least 1 neurodegenerative finding at autopsy and 75.5% had at least 2 neurodegenerative findings. We identified which neuropathologic entities correlate most frequently with one another and demonstrated that the total number of pathologies per individual was directly correlated with cognitive performance as assessed by Clinical Dementia Rating (CDR®) and Mini-Mental State Examination (MMSE). We show that ADNC, LBD, LATE-NC, CVD, hippocampal sclerosis, Pick disease, and FTLD-TDP significantly impact overall cognition as independent variables. More specifically, ADNC significantly affected all assessed cognitive domains, LBD affected attention, processing speed, and language, LATE-NC primarily affected tests related to logical memory and language, while CVD and other less common pathologies (including Pick disease, progressive supranuclear palsy, and corticobasal degeneration) had more variable neurocognitive effects. Additionally, ADNC, LBD, and higher numbers of comorbid neuropathologies were associated with the presence of at least one APOE ε4 allele, and ADNC and higher numbers of neuropathologies were inversely correlated with APOE ε2 alleles. Understanding the mechanisms by which individual and concomitant neuropathologies affect cognition and the degree to which each contributes is an imperative step in the development of biomarkers and disease-modifying therapeutics, particularly as these medical interventions become more targeted and personalized. [ABSTRACT FROM AUTHOR]

Common neurodegenerative diseases feature progressive accumulation of disease-specific protein aggregates in selectively vulnerable brain regions. Increasing experimental evidence suggests that misfolded disease proteins exhibit prion-like properties, including the ability to seed corruptive templating and self-propagation along axons. Direct evidence for transneuronal spread in patients, however, remains limited. To test predictions made by the transneuronal spread hypothesis in human tissues, we asked whether tau deposition within axons of the corticospinal and corticopontine pathways can be predicted based on clinical syndromes and cortical atrophy patterns seen in frontotemporal lobar degeneration (FTLD). Sixteen patients with Pick's disease, 21 with corticobasal degeneration, and 3 with FTLD-MAPT were included, spanning a range of clinical syndromes across the frontotemporal dementia (FTD) spectrum. Cortical involvement was measured using a neurodegeneration score, a tau score, and a composite score based on semiquantitative ratings and complemented by an MRI-based cortical atrophy W-map based on antemortem imaging. Midbrain cerebral peduncle and pontine base descending fibers were divided into three subregions, representing prefrontopontine, corticospinal, and parieto-temporo-occipital fiber pathways. Tau area fraction was calculated in each subregion and related to clinical syndrome and cortical measures. Within each clinical syndrome, there were predicted relationships between cortical atrophy patterns and axonal tau deposition in midbrain cerebral peduncle and pontine base. Between syndromes, contrasting and predictable patterns of brainstem axonal tau deposition emerged, with, for example, greater tau in prefrontopontine fibers in behavioral variant FTD and in corticospinal fibers in corticobasal syndrome. Finally, semiquantitative and quantitative cortical degeneration scores predicted brainstem axonal tau deposition based on anatomical principles. Taken together, these findings provide important human evidence in support of axonal tau spreading in patients with specific forms of tau-related neurodegeneration.

To address the need for more meaningful biomarkers of tauopathies, we have developed an ultrasensitive tau seed amplification assay (4R RT-QuIC) for the 4-repeat (4R) tau aggregates of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and other diseases with 4R tauopathy. The assay detected seeds in 106-109-fold dilutions of 4R tauopathy brain tissue but was orders of magnitude less responsive to brain with other types of tauopathy, such as from Alzheimer's disease cases. The analytical sensitivity for synthetic 4R tau fibrils was ~ 50 fM or 2 fg/sample. A novel dimension of this tau RT-QuIC testing was the identification of three disease-associated classes of 4R tau seeds; these classes were revealed by conformational variations in the in vitro amplified tau fibrils as detected by thioflavin T fluorescence amplitudes and FTIR spectroscopy. Tau seeds were detected in postmortem cerebrospinal fluid (CSF) from all neuropathologically confirmed PSP and CBD cases but not in controls. CSF from living subjects had weaker seeding activities; however, mean assay responses for cases clinically diagnosed as PSP and CBD/corticobasal syndrome were significantly higher than those from control cases. Altogether, 4R RT-QuIC provides a practical cell-free method of detecting and subtyping pathologic 4R tau aggregates as biomarkers.

Microsatellite repeat expansion disease loci can exhibit pleiotropic clinical and biological effects depending on repeat length. Large expansions in C9orf72 (100s-1000s of units) are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). However, whether intermediate expansions also contribute to neurodegenerative disease is not well understood. Several studies have identified intermediate repeats in Parkinson's disease patients, but the association was not found in autopsy-confirmed cases. We hypothesized that intermediate C9orf72 repeats are a genetic risk factor for corticobasal degeneration (CBD), a neurodegenerative disease that can be clinically similar to Parkinson's but has distinct tau protein pathology. Indeed, intermediate C9orf72 repeats were significantly enriched in autopsy-proven CBD (n = 354 cases, odds ratio = 3.59, p = 0.00024). While large C9orf72 repeat expansions are known to decrease C9orf72 expression, intermediate C9orf72 repeats result in increased C9orf72 expression in human brain tissue and CRISPR/cas9 knockin iPSC-derived neural progenitor cells. In contrast to cases of FTD/ALS with large C9orf72 expansions, CBD with intermediate C9orf72 repeats was not associated with pathologic RNA foci or dipeptide repeat protein aggregates. Knock-in cells with intermediate repeats exhibit numerous changes in gene expression pathways relating to vesicle trafficking and autophagy. Additionally, overexpression of C9orf72 without the repeat expansion leads to defects in autophagy under nutrient starvation conditions. These results raise the possibility that therapeutic strategies to reduce C9orf72 expression may be beneficial for the treatment of CBD.

Corticobasal degeneration (CBD) is a clinically heterogeneous tauopathy, which has overlapping clinicopathologic and genetic characteristics with progressive supranuclear palsy (PSP). This study aimed to elucidate whether transactive response DNA-binding protein of 43 kDa (TDP-43) pathology contributes to clinicopathologic heterogeneity of CBD. Paraffin-embedded sections of the midbrain, pons, subthalamic nucleus, and basal forebrain from 187 autopsy-confirmed CBD cases were screened with immunohistochemistry for phospho-TDP-43. In cases with TDP-43 pathology, additional brain regions (i.e., precentral, cingulate, and superior frontal gyri, hippocampus, medulla, and cerebellum) were immunostained. Hierarchical clustering analysis was performed based on the topographical distribution and severity of TDP-43 pathology, and clinicopathologic and genetic features were compared between the clusters. TDP-43 pathology was observed in 45% of CBD cases, most frequently in midbrain tegmentum (80% of TDP-43-positive cases), followed by subthalamic nucleus (69%). TDP-43-positive CBD was divided into TDP-limited (52%) and TDP-severe (48%) by hierarchical clustering analysis. TDP-severe patients were more likely to have been diagnosed clinically as PSP compared to TDP-limited and TDP-negative patients (80 vs 32 vs 30%, P

Tauopathies such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) exhibit characteristic neuronal and glial inclusions of hyperphosphorylated Tau (pTau). Although the astrocytic pTau phenotype upon neuropathological examination is the most guiding feature in distinguishing both diseases, regulatory mechanisms controlling their transitions into disease-specific states are poorly understood to date. Here, we provide accessible chromatin data of more than 45,000 single nuclei isolated from the frontal cortex of PSP, CBD, and control individuals. We found a strong association of disease-relevant molecular changes with astrocytes and demonstrate that tauopathy-relevant genetic risk variants are tightly linked to astrocytic chromatin accessibility profiles in the brains of PSP and CBD patients. Unlike the established pathogenesis in the secondary tauopathy Alzheimer disease, microglial alterations were relatively sparse. Transcription factor (TF) motif enrichments in pseudotime as well as modeling of the astrocytic TF interplay suggested a common pTau signature for CBD and PSP that is reminiscent of an inflammatory immediate-early response. Nonetheless, machine learning models also predicted discriminatory features, and we observed marked differences in molecular entities related to protein homeostasis between both diseases. Predicted TF involvement was supported by immunofluorescence analyses in postmortem brain tissue for their highly correlated target genes. Collectively, our data expand the current knowledge on risk gene involvement (e.g., MAPT, MAPK8, and NFE2L2) and molecular pathways leading to the phenotypic changes associated with CBD and PSP. [ABSTRACT FROM AUTHOR]

Corticobasal degeneration typically progresses gradually over 5–7 years from onset till death. Fulminant corticobasal degeneration cases with a rapidly progressive course were rarely reported (RP-CBD). This study aimed to investigate their neuropathological characteristics. Of the 124 autopsy-confirmed corticobasal degeneration cases collected from 14 centres, we identified 6 RP-CBD cases (4.8%) who died of advanced disease within 3 years of onset. These RP-CBD cases had different clinical phenotypes including rapid global cognitive decline (N = 2), corticobasal syndrome (N = 2) and Richardson's syndrome (N = 2). We also studied four corticobasal degeneration cases with an average disease duration of 3 years or less, who died of another unrelated illness (Intermediate-CBD). Finally, we selected 12 age-matched corticobasal degeneration cases out of a cohort of 110, who had a typical gradually progressive course and reached advanced clinical stage (End-stage-CBD). Quantitative analysis showed high overall tau burden (p = 0.2) and severe nigral cell loss (p = 0.47) in both the RP-CBD and End-stage-CBD groups consistent with advanced pathological changes, while the Intermediate-CBD group (mean disease duration = 3 years) had milder changes than End-stage-CBD (p < 0.05). These findings indicated that RP-CBD cases had already developed advanced pathological changes as those observed in End-stage-CBD cases (mean disease duration = 6.7 years), but within a significantly shorter duration (2.5 years; p < 0.001). Subgroup analysis was performed to investigate the cellular patterns of tau aggregates in the anterior frontal cortex and caudate by comparing neuronal-to-astrocytic plaque ratios between six RP-CBD cases, four Intermediate-CBD and 12 age-matched End-stage-CBD. Neuronal-to-astrocytic plaque ratios of Intermediate-CBD and End-stage-CBD, but not RP-CBD, positively correlated with disease duration in both the anterior frontal cortex and caudate (p = 0.02). In contrast to the predominance of astrocytic plaques we previously reported in preclinical asymptomatic corticobasal degeneration cases, neuronal tau aggregates predominated in RP-CBD exceeding those in Intermediate-CBD (anterior frontal cortex: p < 0.001, caudate: p = 0.001) and End-stage-CBD (anterior frontal cortex: p = 0.03, caudate: p = 0.01) as demonstrated by its higher neuronal-to-astrocytic plaque ratios in both anterior frontal cortex and caudate. We did not identify any difference in age at onset, any pathogenic tau mutation or concomitant pathologies that could have contributed to the rapid progression of these RP-CBD cases. Mild TDP-43 pathology was observed in three RP-CBD cases. All RP-CBD cases were men. The MAPT H2 haplotype, known to be protective, was identified in one RP-CBD case (17%) and 8 of the matched End-stage-CBD cases (67%). We conclude that RP-CBD is a distinct aggressive variant of corticobasal degeneration with characteristic neuropathological substrates resulting in a fulminant disease process as evident both clinically and pathologically. Biological factors such as genetic modifiers likely play a pivotal role in the RP-CBD variant and should be the subject of future research. [ABSTRACT FROM AUTHOR]

The frontotemporal tauopathies all deposit abnormal tau protein aggregates, but often of only certain isoforms and in distinguishing pathologies of five main types (neuronal Pick bodies, neurofibrillary tangles, astrocytic plaques, tufted astrocytes, globular glial inclusions and argyrophilic grains). In those with isoform specific tau aggregates glial pathologies are substantial, even though there is limited evidence that these cells normally produce tau protein. This review will assess the differentiating features and clinicopathological correlations of the frontotemporal tauopathies, the genetic predisposition for these different pathologies, their neuroanatomical selectivity, current observations on how they spread through the brain, and any potential contributing cellular and molecular changes. The findings show that diverse clinical phenotypes relate most to the brain region degenerating rather than the type of pathology involved, that different regions on the MAPT gene and novel risk genes are associated with specific tau pathologies, that the 4-repeat glial tauopathies do not follow individual patterns of spreading as identified for neuronal pathologies, and that genetic and pathological data indicate that neuroinflammatory mechanisms are involved. Each pathological frontotemporal tauopathy subtype with their distinct pathological features differ substantially in the cell type affected, morphology, biochemical and anatomical distribution of inclusions, a fundamental concept central to future success in understanding the disease mechanisms required for developing therapeutic interventions. Tau directed therapies targeting genetic mechanisms, tau aggregation and pathological spread are being trialled, although biomarkers that differentiate these diseases are required. Suggested areas of future research to address the regional and cellular vulnerabilities in frontotemporal tauopathies are discussed. [ABSTRACT FROM AUTHOR]

Filamentous tau pathologies are hallmark lesions of several neurodegenerative tauopathies including Alzheimer's disease (AD) and corticobasal degeneration (CBD) which show cell type-specific and topographically distinct tau inclusions. Growing evidence supports templated transmission of tauopathies through functionally interconnected neuroanatomical pathways suggesting that different self-propagating strains of pathological tau could account for the diverse manifestations of neurodegenerative tauopathies. Here, we describe the rapid and distinct cell type-specific spread of pathological tau following intracerebral injections of CBD or AD brain extracts enriched in pathological tau (designated CBD-Tau and AD-Tau, respectively) in young human mutant P301S tau transgenic (Tg) mice (line PS19) ~6-9 months before they show onset of mutant tau transgene-induced tau pathology. At 1 month post-injection of CBD-Tau, tau inclusions developed predominantly in oligodendrocytes of the fimbria and white matter near the injection sites with infrequent intraneuronal tau aggregates. In contrast, injections of AD-Tau in young PS19 mice induced tau pathology predominantly in neuronal perikarya with little or no oligodendrocyte involvement 1 month post-injection. With longer post-injection survival intervals of up to 6 months, CBD-Tau- and AD-Tau-induced tau pathology spread to different brain regions distant from the injection sites while maintaining the cell type-specific pattern noted above. Finally, CA3 neuron loss was detected 3 months post-injection of AD-Tau but not CBD-Tau. Thus, AD-Tau and CBD-Tau represent specific pathological tau strains that spread differentially and may underlie distinct clinical and pathological features of these two tauopathies. Hence, these strains could become targets to develop disease-modifying therapies for CBD and AD. [ABSTRACT FROM AUTHOR]

In order to determine the frequency of microtubule-associated protein tau gene ( MAPT) mutations and rare variants in CBD, we performed a systematic sequence analysis of MAPT coding and 3′ untranslated region (3′UTR) in a large cohort of autopsy-confirmed CBD patients ( N = 109). This identified a novel MAPT mutation in exon 13, p.N410H, in a case that is neuropathologically indistinguishable from sporadic CBD. On immunoblot, the p.N410H mutation carrier had the same insoluble tau profile as seen in CBD. Additionally, tau expression analysis in brain tissue found a significant increase in the 4R/3R tau mRNA ratio ( P = 0.04), indicating that p.N410H disrupts tau isoform homeostasis. Biochemically, recombinant tau protein with p.N410H showed a marked increase in tau filament formation compared to wild-type tau ( P < 0.001), had a 19.2 % decrease in rate of microtubule assembly ( P < 0.05), and a 10.3 % reduction in the extent of total microtubule polymerization ( P < 0.01). Sequence analysis of the complete MAPT 3′UTR in autopsy-confirmed CBD cases further identified two rare variants with nominally significant association with CBD. An ATC nucleotide insertion ('MAPTv8') was found in 4.6 % of CBD patients compared to 1.2 % of controls ( P = 0.031, OR = 3.71), and rs186977284 in 4.6 % CBD patients, but only 0.9 % of controls ( P = 0.04, OR = 3.58). Rs186977284 was also present in 2.7 % of a large cohort of autopsy-confirmed PSP patients ( N = 566) and only 0.9 % of an additional control series ( P = 0.034, OR = 3.08), extending the association to PSP. Our findings show that mutations in MAPT can cause CBD and MAPT non-coding variants may increase the risk of complex 4R tauopathies. [ABSTRACT FROM AUTHOR]

Corticobasal degeneration (CBD) is a disorder affecting cognition and movement due to a progressive neurodegeneration associated with distinctive neuropathologic features, including abnormal phosphorylated tau protein in neurons and glia in cortex, basal ganglia, diencephalon, and brainstem, as well as ballooned neurons and astrocytic plaques. We identified three cases of CBD with olivopontocerebellar atrophy (CBD-OPCA) that did not have α-synuclein-positive glial cytoplasmic inclusions of multiple system atrophy (MSA). Two patients had clinical features suggestive of progressive supranuclear palsy (PSP), and the third case had cerebellar ataxia thought to be due to idiopathic OPCA. Neuropathologic features of CBD-OPCA are compared to typical CBD, as well as MSA and PSP. CBD-OPCA and MSA had marked neuronal loss in pontine nuclei, inferior olivary nucleus, and Purkinje cell layer. Neuronal loss and grumose degeneration in the cerebellar dentate nucleus were comparable in CBD-OPCA and PSP. Image analysis of tau pathology showed greater infratentorial tau burden, especially in pontine base, in CBD-OPCA compared with typical CBD. In addition, CBD-OPCA had TDP-43 immunoreactive neuronal and glial cytoplasmic inclusions and threads throughout the basal ganglia and in olivopontocerebellar system. CBD-OPCA met neuropathologic research diagnostic criteria for CBD and shared tau biochemical characteristics with typical CBD. These results suggest that CBD-OPCA is a distinct clinicopathologic variant of CBD with olivopontocerebellar TDP-43 pathology. [ABSTRACT FROM AUTHOR]

Numerous families exhibiting both frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) have been described, and although many of these have been shown to harbour a repeat expansion in C9ORF72, several C9ORF72-negative FTD-ALS families remain. We performed neuropathological and genetic analysis of a large European Australian kindred (Aus-12) with autosomal dominant inheritance of dementia and/or ALS. Affected Aus-12 members developed either ALS or dementia; some of those with dementia also had ALS and/or extrapyramidal features. Neuropathology was most consistent with frontotemporal lobar degeneration with type B TDP pathology, but with additional phosphorylated tau pathology consistent with corticobasal degeneration. Aus-12 DNA samples were negative for mutations in all known dementia and ALS genes, including C9ORF72 and FUS. Genome-wide linkage analysis provided highly suggestive evidence (maximum multipoint LOD score of 2.9) of a locus on chromosome 16p12.1-16q12.2. Affected individuals shared a chromosome 16 haplotype flanked by D16S3103 and D16S489, spanning 37.9 Mb, with a smaller suggestive disease haplotype spanning 24.4 Mb defined by recombination in an elderly unaffected individual. Importantly, this smaller region does not overlap with FUS. Whole-exome sequencing identified four variants present in the maximal critical region that segregate with disease. Linkage analysis incorporating these variants generated a maximum multipoint LOD score of 3.0. These results support the identification of a locus on chromosome 16p12.1-16q12.2 responsible for an unusual cluster of neurodegenerative phenotypes. This region overlaps with a separate locus on 16q12.1-q12.2 reported in an independent ALS family, indicating that this region may harbour a second major locus for FTD-ALS. [ABSTRACT FROM AUTHOR]

Sporadic tauopathies are characterized by differential cellular and topographical predominance of phospho-tau immunoreactivity and biochemical distinction of the tau protein. Established entities include progressive supranuclear palsy, corticobasal degeneration, Pick's disease, and argyrophilic grain disease. During a community-based longitudinal study on aging, we detected tau pathologies not compatible with these categories. We immunostained for different phospho-tau epitopes, 4R and 3R tau isoforms, α-synuclein, amyloid-β, and phospho-TDP-43, analyzed the MAPT and ApoE genes, and performed western blotting for the tau protein. The mean age of patients (4 women, 3 men) was 83.8 years. Clinical presentations combined dementia with psychiatric symptoms and/or parkinsonism. In addition to neurofibrillary tangles and diffuse neuronal cytoplasmic tau immunoreactivity, the neuropathology was characterized by peculiar cytopathologies (diffuse granular immunopositivity of astrocytic processes and patchy accumulation of thin threads) in a distinctive distribution (frontal and temporal cortices, hippocampus, amygdala, basal ganglia, locus coeruleus, and substantia nigra). Argyrophilic grains were detected in four patients. Few to moderate densities of neuritic plaques but widespread phospho-TDP-43 pathology was observed in five patients. There was variability in the H1/H2 and ApoE alleles and biochemical features of tau protein. We propose these cases as complex tauopathy with a characteristic constellation: some features of primary tauopathies and Alzheimer's disease mixed with additional cytopathologies including a distinctive astrogliopathy, in a characteristic distribution of lesions. These complex tauopathies in the elderly deserve specific diagnostic and eventually therapeutic considerations. [ABSTRACT FROM AUTHOR]

A man aged 55 with negative family history presented with progressive decline in spatial orientation and visual functions for 2 years. He showed impaired optic fixation, optic ataxia, agraphia, acalculia, ideomotor apraxia, disturbed right–left differentiation but preserved color matching, memory and motor perception, gradually progressing to dementia, without extrapyramidal signs. Brain MRI and PET showed severe bilateral atrophy and hypometabolism in parieto-occipital areas with sparing of visual perception area and frontal lobes. Treatment with cholinesterase inhibitors had no effect. Death occurred 6½ years after onset of symptoms from bronchopneumonia. Clinical diagnosis was posterior cortical atrophy (Benson’s syndrome). Autopsy showed severe bilateral parietal cortical atrophy, less severe in other brain regions without subcortical lesions. Histology revealed severe diffuse tauopathy with neuronal loss, neurofibrillary tangles, neuropil threads, and tau deposits in astroglia and oligodendroglia in parietal, temporal, occipital cortex, less in frontal cortex and hippocampus, putamen, claustrum, thalamus and subthalamus. Severely involved white matter showed many tau-positive threads, comma-like inclusions in oligodendroglia (coiled bodies) and in astroglia. Mild neuronal loss in substantia nigra was associated with massive tau pathology, also involving several brainstem nuclei, cerebellum being preserved. There were neither astrocytic plaques nor any amyloid pathology. Neuronal and glial inclusions were generally 4R-tau-positive and 3R-tau-negative. No TDP-43 and a-synuclein inclusions were detected. Spinal cord was not available. No mutations were found in the MAPT gene. This is the first published case with the fully developed clinical and neuroimaging picture of posterior cortical atrophy, morphologically presenting as a distinct phenotype of 4R-tauopathy that closely resembles (atypical) CBD. [ABSTRACT FROM AUTHOR]

Sporadic corticobasal syndrome (CBS) has been associated with diverse pathological substrates, but frontotemporal lobar degeneration with TDP-43 immunoreactive inclusions (FTLD-TDP) has only been linked to CBS among progranulin mutation carriers. We report the clinical, neuropsychological, imaging, genetic, and neuropathological features of GS, a patient with sporadic corticobasal syndrome. Genetic testing revealed no mutations in the microtubule associated protein tau or progranulin ( PGRN) genes, but GS proved homozygous for the T allele of the rs5848 PGRN variant. Autopsy showed ubiquitin and TDP-43 pathology most similar to a pattern previously associated with PGRN mutation carriers. These findings confirm that FTLD-TDP should be included in the pathological differential diagnosis for sporadic CBS. [ABSTRACT FROM AUTHOR]

We report two sporadic cases of tauopathy with unusual neuropathological features. The ages of the patients at death were 86 and 74 years, and the disease durations were 4 and 3 years, respectively. The former patient showed progressive dementia and amyotrophy (autopsy revealed that severe cervical spondylosis was responsible for the amyotrophy), and the latter showed progressive parkinsonism and dementia. The essential brain pathologies were similar to each other; although ballooned neurons and astrocytic tau lesions (astrocytic plaques) were present in the affected cerebral cortex, the most striking finding was focal, much heavier accumulation of tau in the subcortical white matter. Moreover, double-labeling immunostaining, as well as Gallyas–Braak electron and AT8 immunoelectron microscopic studies strongly suggested that in the affected subcortical white matter, the accumulation of tau occurred mainly in the astrocytic processes. In the latter patient, for whom frozen brain tissue was available, immunoblotting of insoluble tau revealed a pattern compatible with that obtained from brain affected by typical corticobasal degeneration (CBD), and gene analysis of tau revealed no mutations, with a H1 haplotype. Finally, in both cases, the pathological diagnosis of CBD was considered to be appropriate. However, the tau pathology affecting the subcortical white matter astrocytes was very unusual for the disease. [ABSTRACT FROM AUTHOR]

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a rare autosomal dominant disorder characterized by cerebral white matter degeneration with axonal spheroids leading to progressive cognitive and motor dysfunction. We report clinical and pathological features, as well as molecular genetic analysis, of a family with HDLS. A pedigree consisting of 27 persons in 5 generations contained 6 affected individuals. Dementia and depression were common; two individuals presented with a syndrome resembling corticobasal degeneration (CBD). Postmortem neuropathologic evaluation of three affected individuals revealed enlargement of the lateral ventricles and marked attenuation of cerebral white matter, but preservation of white matter in brainstem and cerebellum, except for the corticospinal tract. Histopathologic studies showed a loss of myelinated fibers, lipid-laden macrophages and bizarre astrocytes, as well as abundant axonal spheroids that were immunoreactive for phosphorylated neurofilament protein and amyloid precursor protein (APP), but not αB-crystallin and variably with ubiquitin. By electron microscopy, axonal spheroids contained aggregates of intermediate filaments or of organelles that were predominantly vesicular and lamellar. The cerebral cortex had focal neuronal degeneration with αB-crystallin-immunoreactive ballooned neurons. In summary, the present report describes a previously unreported kindred with HDLS with individuals presenting as CBD. Immunohistochemistry for APP and αB-crystallin demonstrates distinctive neurodegeneration in cerebral axons and perikarya. [ABSTRACT FROM AUTHOR]

The purpose of this study was to learn about possible variations in phospho-tau profiles in terms of case-to-case differences, regional modifications and diversification of tau phosphorylation sites in five PSP cases with moderate to severe frontosubcortical dysfunction. Gel electrophoresis of sarkosyl-insoluble fractions and Western blotting with five anti-tau phospho-specific antibodies directed to phosphorylation sites Thr181, Ser202, Ser214, Ser396 and Ser422 were used to study four brain regions including frontal cortex, area 8, subcortical white matter of the frontal lobe, caudate/putamen: striatum, and basis pontis: pons. Although two bands of 66 and 62 kDa were observed in almost every region in each case, the intensity of the bands depends on the anti-tau phospho-specific antibody. More importantly, bands of 72, 50/55 and 37 kDa were commonly found in PSP brains, whereas other bands of about 60, 42, 33 and 29 kDa were irregularly observed. The pattern of bands differed slightly from one case to another and from one region to another. Moreover, the phospho-tau profile differed depending on the anti-tau phospho-specific antibody used. These data suggest that several species of tau are variably phosphorylated at a given time in a given region (and probably in a given cell), and that tau aggregates are composed of several phosphorylated truncated or cleaved tau molecules, in addition to phosphorylated complete tau isoforms. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD), Pick’s disease (PiD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and dementia with Lewy bodies (DLB) are diseases associated with the accumulation of tau or α-synuclein. In AD, β-amyloid (Aβ)-associated caspase activation and cleavage of tau at Asp421 (ΔTau) may be an early step in neurofibrillary tangle (NFT) formation. To examine whether ΔTau accumulates in other diseases not characterized by extracellular Aβ accumulation, we examined PiD, PSP, and CBD cases in comparison to those without extensive tau accumulation including frontotemporal lobar degeneration without Pick bodies (FTLD) and control cases. Additionally, we studied ΔTau accumulation in DLB cases associated with intracellular α-synuclein. ΔTau was observed in all disease cases except non-PiD FTLD and controls. These results demonstrate that the accumulation of ΔTau may represent a common pathway associated with abnormal accumulation of intracellular tau or α-synuclein and may be relatively less dependent on the extracellular accumulation of Aβ in non-AD dementias. [ABSTRACT FROM AUTHOR]

Microtubule-associated protein tau is the major component of the filamentous neurofibrillary lesions of Alzheimer’s disease (AD) and other tauopathies. Recently, it has been reported that tau isoforms lacking both N-terminal exon 2 and exon 3 do not form straight filament- or paired helical filament-like filaments in vitro, and that the N-terminal exons facilitate assembly of full-length tau. However, neuropathological and biological studies on the N-terminal region of tau protein in human tissue have been limited. We performed a biochemical study on the abnormally phosphorylated tau in brains affected by AD and corticobasal degeneration (CBD), and an immunohistochemical study on tau-positive structures in neurodegenerative diseases, to clarify whether tau with the exon 3 insert was present in abnormal tau-positive structures. On immunoblots of sarkosyl-insoluble tau, anti-exon 3 antibody (anti-E3 Ab) recognized two bands of 68 and 72 kDa in AD and only one band of 72 kDa in CBD. Immunohistochemically, anti-E3 Ab recognized most parts of the neurofibrillary tangles (NFT) in AD and Pick bodies in Pick’s disease. In progressive supranuclear palsy (PSP) and CBD, most NFT and pretangles were positive for anti-E3 Ab, as were a small number of glial inclusions. These results indicate that abnormally phosphorylated tau containing the exon 3 insert is present in both PSP and CBD brain, and that CBD cannot be distinguished from PSP by immunoreactivity for anti-E3 Ab. Although most intraglial inclusions were negative for anti-E3 Ab, a few were positive. Therefore, tau isoforms containing the exon 3 insert are expressed at low levels in glial cells. [ABSTRACT FROM AUTHOR]

We examined spinal cord lesions in eight patients with a pathological diagnosis of corticobasal degeneration (CBD). Using Gallyas-Braak (G-B) staining or AT-8 tau immunostaining, a few neuropil threads were identified in the white matter of the CBD spinal cords, mainly in the anterior funiculus, whereas the posterior funiculus was well preserved without threads. In the gray matter of the CBD spinal cords, particularly in the intermediate gray matter, there were widespread neuropil threads and neuronal inclusions. Large motor neurons in the anterior horn, neurons in the intermediolateral column, and Clarke’s column were relatively well preserved from neuronal loss and gliosis. Neuronal inclusions were of the globose type, suggestive of neurofibrillary tangles (NFTs), or showed diffuse granular accumulations of cytoplasmic tau, suggestive of pretangles. No typical NFTs, recognized by Bodian silver staining, were identified. The distribution of neuropil threads and G-B- or AT-8 tau-positive small neurons resembled that of interneurons. No astrocytic plaques were present in any of the CBD spinal cords, and only a few coiled bodies were seen. Neuropil threads in the white and gray matter and neuronal inclusions in the gray matter were prominent in cervical segments, and their density decreased caudally. We suggest that the presence of neuropil threads, particularly in the cervical intermediate gray matter, and the presence of neuronal inclusions, particularly in cervical interneurons, is an essential pathological feature of CBD. [ABSTRACT FROM AUTHOR]

This report concerns a clinicopathological study of three additional patients with corticobasal degeneration (CBD), described here for the first time, and a clinicopathological correlation between pyramidal signs and upper motor neuron involvement, in ten autopsy cases of CBD, including seven cases reported by us previously. We investigated pyramidal signs, including hyperreflexia, Babinski sign, and spasticity, and involvement of the primary motor cortex and pyramidal tract, focusing on the astrocytosis of the fifth layer of the primary motor cortex. Pyramidal signs were observed in six (60%) of the ten cases. Hyperreflexia was evident in six patients (60%), with spasticity being observed in three patients (30%). Loss of Betz cells associated with prominent astrocytosis and presence of ballooned neurons in the fifth layer of the primary motor cortex was observed in all ten cases. In all cases, involvement of the pyramidal tract was obvious in the medulla oblongata, without involvement of the pyramidal tract in the midbrain. Constant and severe involvement of the fifth layer of the primary motor cortex, including the Betz cells, has not previously been reported in CBD. We suggest that the pyramidal signs in CBD have been disregarded. [ABSTRACT FROM AUTHOR]

Oxidative stress including DNA oxidation is implicated in Parkinson’s disease (PD). We postulated that DNA repair enzymes such as 8-oxoguanosine DNA glycosylase (OGG1) are involved in the PD process. We performed immunohistochemical and biochemical studies on brains of patients with PD and those of patients with progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) as disease controls, and control subjects. We found higher expression levels of mitochondrial isoforms of OGG1 enzymes in the substantia nigra (SN) in cases of PD. Furthermore, Western blot analysis revealed high OGG1 levels in the SN of the patients with PD. Our results indicate the importance of oxidative stress within the susceptible lesions in the pathogenesis of PD. [ABSTRACT FROM AUTHOR]

We report two patients who exhibited frontotemporal dementia (FTD) with unusual neuropathological features. The ages of the patients at death were 65 and 67 years, the disease durations were 6 and 5 years, and the clinical diagnoses were Pick’s disease and corticobasal degeneration (CBD), respectively. At autopsy, both cases exhibited neuropathological findings compatible with those of CBD, including atrophy of the frontal and parietal lobes, neuronal loss and gliosis in the cortical and subcortical regions, and presence of cortical ballooned neurons and astrocytic plaques (APs). In both cases, immunoblotting of insoluble tau exhibited the pattern of selective accumulation of four-repeat tau, a finding that is also compatible with CBD. However, severe degeneration was evident in the frontal and parietal white matter in both cases. Moreover, a striking finding was the widespread presence in the affected cortex of tufted astrocytes (TAs), which are characteristic of progressive supranuclear palsy (PSP). Neither co-occurrence of APs and TAs nor severe degeneration of the cerebral white matter is a feature of either CBD or PSP. No mutations were found in the tau gene in either case. In conclusion, the possibility that these two cases represent a new neuropathological phenotype of non-familial FTD rather than simply a variant of CBD cannot be completely excluded. [ABSTRACT FROM AUTHOR]

The clinical, neuroradiological, neuropathological and biochemical findings in four patients with primary progressive aphasia and tauopathy are described. The aphasic syndrome preceded by several years the appearance of other symptoms in every case. Asymmetrical apraxia with alien hand phenomenon occurred in one case. Frontotemporal symptoms occurred in three cases, but progressed to dramatic cognitive devastation in only one of these. Generalized dementia consistent with probable Alzheimer's disease (AD) developed with time in another. Cerebral computer tomography scans, magnetic resonance imaging and SPECT studies revealed marked asymmetries in one case, and showed nonspecific cerebral atrophy in the remaining ones. The neuropathological examination revealed typical corticobasal degeneration (CBD) in one case; CBD and AD in another; and atypical CBD, argyrophilic grain disease (AGD) and α-synucleinopathy consistent with Parkinson's disease in a third. Unique neuropathological findings were found in the remaining case. This was characterized by severe cerebral atrophy, marked neuronal loss in the cerebral cortex and abnormal tau deposition in neurons of the cerebral cortex, diencephalon and brain stem. Ballooned neurons, Pick bodies, generalized cortical neurofibrillary tangles and astrocytic plaques were absent. However, massive globular inclusions, containing phospho-tau, occurred in glial cells, mainly oligodendrocytes, in the white matter. Biochemical studies of frontal homogenates revealed four bands of 73/74, 68, 64 and 60 kDa of phosphorylated tau (using antibodies recognizing phospho-tau Thr181, Ser262 and Ser422) in the patient with AD and CBD, suggesting a predominant AD pattern in this case. Two bands of 68 and 64 kDa of phospho-tau were recovered in the sarkosyl-insoluble fraction in the other three cases. This pattern is similar to that found in CBD, progressive supranuclear palsy and AGD. Taken together, the present series further supports pure and combined CBD as causes of primary progressive aphasia, and they extend the hypothesis that primary progressive aphasia may be the initial symptom of distinct tauopathies. [ABSTRACT FROM AUTHOR]

We report a 67-year-old man with 4-repeat (4R) tauopathy sharing both features of corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). Although CBD and PSP have a common pathological feature that 4R tau accumulates in neurons and glia, recent pathological studies have confirmed differences between the two disorders. Clinical features of the present case were asymmetrical apraxia, parkinsonism, memory disturbance, disorientation and left limb myoclonus with a 5-year history. Pathological features were the widespread occurrence of 4R tau-positive structures including pre-tangles, neurofibrillary tangles, astrocytic plaques, tufted astrocytes, coiled bodies and argyrophilic threads. Biochemically, immunoblotting of insoluble tau demonstrated the low molecular fragments of 37 kDa and 33 kDa observed in typical CBD and PSP, respectively, in addition to the presence of 4R tau isoforms. The present case shared tau-related pathological and biochemical features of CBD and PSP. These findings support that CBD and PSP are closely associated disorders having a pathogenesis common to 4R tauopathy. [ABSTRACT FROM AUTHOR]

Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) have some clinical and pathological features in common. Each, however, has been shown to have specific astrocytic inclusions. CBD is characterized by astrocytic plaques, and PSP is characterized by tuft-shaped astrocytes. To clarify differences between these inclusions, we investigated intracerebral distribution of astrocytic plaques and tuft-shaped astrocytes in autopsied brains of patients with either CBD or PSP. Specimens from ten patients with CBD and five patients with PSP were stained by the Gallyas-Braak method. Densities of the astrocytic plaques and tuft-shaped astrocytes were determined for 11 cerebral cortical regions, 6 subcortical nuclei, 5 brain stem regions, the cerebellar cortex and the dentate nucleus. Astrocytic plaques were most abundant in the prefrontal and premotor areas in the cerebral cortex of CBD brains, whereas tuft-shaped astrocytes were most prominent in the precentral gyrus and premotor area of PSP brains. Many astrocytic plaques were observed in the caudate nucleus of CBD brains, whereas tuft-shaped astrocytes were abundant in both the caudate and putamen and moderate in number in the globus pallidus, subthalamic nucleus and thalamus in PSP brains. Very slight accumulation of astrocytic plaques was seen in the brain stem of CBD brains, whereas numerous tuft-shaped astrocytes were found in the red nucleus and superior colliculus of PSP brains. Distribution of the astrocytic plaques and tuft-shaped astrocytes differed greatly. Thus, CBD and PSP can be considered different entities. [ABSTRACT FROM AUTHOR]

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are clinically characterized by atypical parkinsonism and cognitive disorders and classified in the same histopathological category showing neuronal and glial neurofibrillary tangles (NFTs). To characterize the vulnerability of the forebrain and midbrain cholinergic systems in PSP and CBD, we performed a comparative study of cholinergic neuronal changes in the nucleus basalis of Meynert (NBM) and the laterodorsal tegmental and pedunculopontine tegmental nuclei (LdtgN and PptgN) of brains obtained at autopsy (three cases of PSP, one case of CBD and six cases without neurological diseases) by immunohistochemistry for choline acetyltransferase (ChAT) and Gallyas-Braak staining. In the NBM, the number of neurons and the ChAT-positivity rate of remaining neurons were decreased more in CBD than PSP. On the other hand, in the PptgN and LdtgN neurons were reduced much more, and more NFTs were observed in PSP than CBD. PSP showed a severe decrease of neurons and the ChAT-immunopositive neurons in the LdtgN but less in the PptgN. In CBD, there was a mild deletion of the ChAT-immunostained neurons in the PptgN, but not in the LdtgN. In PSP, cholinergic neurons in the LdtgN are likely to be more vulnerable than PptgN and NBM. [ABSTRACT FROM AUTHOR]

Tau phosphorylation was examined in Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) using phospho-specific tau antibodies recognizing the phosphorylated form of Ser202, Ser214 and Ser 396, and antibodies to non-phosphorylated glycogen synthase kinase-3α/β (GSK-3α/β), which regulates phosphorylation at these specific sites on tau and phosphorylated GSK-3βSer9 (GSK-3β-P); this antibody is directed to the inactive form of GSK-3β. Phospho-specific tau antibodies recognized disease-specific band patterns on Western blots of sarcosyl-insoluble fractions: four bands of 73, 68, 64 and 60 kDa in AD, two bands of 68 and 64 kDa in PSP and CBD, and two bands of 64 and 60 kDa in PiD. Moreover, anti-phospho-tau Ser202, Ser214 and Ser369 decorated neurons with neurofibrillary tangles, dystrophic neurites of senile plaques, neuropil threads, Pick bodies, astrocytes and oligodendrocytes with coiled bodies. No differences in the expression of GSK-3α/β were seen between neurons with and without neurofibrillary tangles. GSK-3α/β was enriched in sarcosyl-insoluble fractions, suggesting association of this kinase with tau hyperphosphorylation. In addition, strong expression of the phosphorylated form of GSK-3β was found in a subpopulation of neurons with neurofibrillary tangles, and in dystrophic neurites of senile plaques, neuropil threads, Pick bodies, tau-containing astrocytes and coiled bodies in AD, PiD, PSP and CBD. This was not due to cross-reactivity between GSK-3 and phospho-tau. Specific bands differing from those of phospho-tau were seen on Western blots of sarcosyl-insoluble fractions processed for GSK-3α/β and GSK-3β-P. Double-labeling immunohistochemistry discloses that GSK-3β-P co-localizes with abnormal tau in about 50% of neurons with neurofibrillary tangles, and in neuronal processes, astrocytes and oligodendrocytes in various tauopathies. The present results support a pivotal role for GSK-3 in tau phosphorylation in neurons and glial cells. Moreover, the elevated number of tau-containing cells stained with anti-GSK-3β-P antibodies suggests a partial inactivation of the kinase, or sequestration of the phosphorylated form, which may contribute to the regulation of the cascade of tau hyperphosphorylation in tauopathies, and to protect tau-containing cells from apoptosis. [ABSTRACT FROM AUTHOR]

The rabbit polyclonal anti-tau phospho-specific Ser262 antibody (577814 Calbiochem) recognizes disease-specific band patterns on Western blots of sarkosyl-insoluble fractions in Alzheimer's disease (AD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), argyrophilic grain disease (AGD) and Pick's disease (PiD): four bands of 74/72, 68, 64 and 60 kDa in AD, two bands of 68 and 64 kDa in PSP, CBD and AGD, and two bands of 64 and 60 kDa in PiD. Moreover, anti-tau phospho-specific Ser262 decorates neurons with neurofibrillary tangles, neurons with pre-tangles, dystrophic neurites of senile plaques, neuropil threads, Pick bodies, argyrophilic grains, and coiled bodies. Achromatic neurons in CBD, ballooned neurons in AGD, tufted astrocytes in PSP, astrocytic plaques in CBD and tau-containing astrocytes in AGD are not immunostained with the anti-tau phospho-specific Ser262 antibody. The lack of phospho-specific Ser262 immunoreactivity in tau-containing inclusions in astrocytes suggests different kinase equipment and activation in comparing neurons and astrocytes in tauopathies. Pick bodies in PiD and grains in AGD are weakly, or not all, immunostained in tissue samples with long post-mortem delays, although Ser262 is preserved in brain homogenates corresponding to the same time points processed for Western blot. This indicates postmortem modifications of tau in Pick bodies and argyrophilic grains, but not in other tau-containing inclusions, including paired helical filaments and coiled bodies, and suggests differences in tau conformation, particularly that involving phospho-tauSer262 among tauopathies. However, it is important to note that phosphorylation of tau at Ser262 does occur in Pick bodies and argyrophilic grains, and this may have important consequences in reducing the capacity of binding phospho-tau to microtubules in these inclusions. [ABSTRACT FROM AUTHOR]

We report an autopsy case of a 77-year-old Japanese man with a 7-year history of progressive unilateral left limb dystonia and arm levitation. Brain computed tomography showed fronto-temporal atrophy. The patient was diagnosed as having corticobasal degeneration. Histopathologically, the cerebral cortices, especially of the parasagittal region, and subcortical nuclei revealed numerous Gallyas/tau-positive cytoplasmic inclusions characteristic of progressive supranuclear palsy (PSP). Grumose degeneration was evident in the dentate nucleus. Astrocytic plaques were not present, but a small number of ballooned neurons were found in the fronto-temporal regions. The involvement by the PSP lesions was quite asymmetric in the affected areas, including the frontal cortices, basal ganglia, red nuclei, and inferior olivary nuclei, being more prominent on the side contralateral to the side of limb dystonia. The apparent unilateral dominance of PSP pathology may be relevant to the asymmetric clinical presentation of this patient. [ABSTRACT FROM AUTHOR]

Progressive supranuclear palsy (PSP) is a sporadic multisystem neurodegenerative disorder that is one of the major causes of parkinsonism, which shares common biochemical and genetic features with corticobasal degeneration (CBD). Ballooned neurons (BN) are one of the histopathologic hallmarks of CBD and their presence is a neuropathologic feature that helps differentiate PSP from CBD, since BN are uncommon in PSP. There are, however, several reports in the literature of BN in PSP. BN are also a consistent finding in argyrophilic grain disease (AGD), where they are relatively confined to limbic structures, in particular the amygdala. Since AGD has been found with increased frequency in PSP, it is possible that cases of PSP with BN may represent co-existing AGD. In the present study, we investigated this possibility by studying the distribution and the density of BN with αB-crystallin immunostaining in 20 cases of PSP, including equal numbers of cases with and without co-existing AGD. In PSP cases with concurrent AGD, BN were consistently found in limbic areas, but in pure PSP cases, BN were rare, supporting the hypothesis that concurrent AGD may account for most cases of PSP with BN. [ABSTRACT FROM AUTHOR]

Immunohistochemical localization of tau in the cerebellar cortex was carried out using a mouse monoclonal antibody against phosphorylation-dependent tau (AT8) in brain tissue (cerebellum) from 13 patients with progressive supranuclear palsy (PSP), 7 patients with corticobasal degeneration (CBD) and 5 age-matched control subjects. Purkinje cell somata that showed diffuse granular accumulation of cytoplasmic tau were found occasionally in 9 of the 13 patients with PSP (69%) and in 4 of the 7 patients with CBD (57%). Tau-positive doughnut-shaped structures were also found occasionally in the cerebellar molecular layer in 6 of the 13 patients with PSP (46%) and 2 of the 7 patients with CBD (29%). No tau immunoreactivity was detected in the cerebellar cortex in the control tissue. In the tissue from one patient with PSP, we also performed a double-labeling immunofluorescence study with anti-glial fibrillary acidic protein (GFAP) antibody and AT8, as well as an immuno-electron microscopic study with AT8. In tau-positive Purkinje cell somata and dendrites, the reaction product was localized mainly within the rough endoplasmic reticulum and free ribosomes. Tau-positive doughnut-shaped structures were located in the GFAP-positive radial processes of Bergmann's glia and were present in the outer areas of inclusions reminiscent of Lewy bodies, which consist of aggregated pathological tau filaments. In conclusion, we have demonstrated a novel tau pathology that affects Purkinje cells and Bergmann's glia in patients with PSP and CBD, indicating that the cerebellar cortex can be involved in the disease processes in PSP and CBD. [ABSTRACT FROM AUTHOR]

A 65-year-old woman was admitted to our hospital for forgetfulness, depression and eccentric behavior that had been first noticed 2 years prior to admission. She showed memory impairment, perseveration and repeated violent actions, but no limb-kinetic apraxia. She died 12 years after the onset of symptoms. At autopsy, the unfixed brain weighed 820 g. Atrophy was circumscribed in the frontal lobe on both sides. The globus pallidus and the caudate nucleus were markedly atrophic and gold yellow in color, and the substantia nigra was strikingly pale. The cortical area showed neuronal loss and status spongiosus of the second and third cortical layers with ballooned neurons. Marked neuronal loss was observed in the dorsomedial nucleus of the thalamus, Meynert basal nucleus and substantia nigra. With Holzer stain, fibrillary gliosis was found to be severe in the frontal lobe, globus pallidus, subthalamic nucleus, hippocampus, dorsomedial nucleus of thalamus, substantia nigra, pontine tegmentum and inferior olivary nucleus. With Bielschowsky-Hirano stain, neurofibrillary tangles were observed in the cortex, hippocampus, substantia nigra, dentate nucleus, subthalamic nucleus, pontine nucleus, the inferior olivary nucleus, dorsomedial nucleus of the thalamus and, to a lesser extent, the neostriatum. Strikingly numerous argyrophilic and tau-positive threads were present in the cerebral white matter. These neuropathological findings corresponded to corticobasal degeneration, but lesions characteristic of progressive supranuclear palsy were also found. Moreover, widespread iron deposition throughout the central nervous system was the most striking finding of the present case. To our knowledge, such a case has not been reported in the literature to date. [ABSTRACT FROM AUTHOR]

In corticobasal degeneration (CBD), tau-positive cytoplasmic inclusions resembling Pick bodies (PBs) appear in the cerebral cortex. Tau immunoreactivity in PBs is expressed mainly on filamentous elements, whereas that of PB-like inclusions in CBD is expressed on granules, which are densely packed mainly in the periphery of inclusions. PBs are clearly detectable by conventional Bodian silver impregnation but negative for the Gallyas–Braak (G–B) method and for PS262, which recognizes phosphorylation at Ser 262 of the entire tau sequence. Almost all PBs are negative for Ex10, which recognizes 4-repeat tau specifically. In contrast to PBs, PB-like inclusions in CBD could not be detected by the Bodian method, but were positive for the G–B method, PS262 and Ex10. In summary, PBs and PB-like inclusions exhibit distinct differences. These results are useful for the argument of an overlap between PiD and CBD as well as discussion of the phenotypic resemblance of PB-like inclusions bearing types of FTDP-17 to Pick's disease. [ABSTRACT FROM AUTHOR]

We investigated four Japanese autopsy cases of the generalized variant of Pick's disease ("basophilic inclusion body disease") both clinically and pathologically, and examined the degree and distribution of the basal ganglia lesions, including the amygdala, striatum, pallidum, and substantia nigra. The lesions in the amygdala, striatum, and pallidum were classified into three categories (slight, moderate, and severe). The lesions in the substantia nigra were qualitatively judged, compared with normal controls. Extrapyramidal signs, not noticed in the generalized variant of Pick's disease, were evident in all four cases, in addition to dementia. The degree and distribution of basal ganglia lesions in all four cases were uniform: the caudate nucleus showed severe lesions, the amygdala and putamen severe to moderate lesions, and the pallidum moderate to slight lesions. The substantia nigra in all our cases showed prominent neuronal loss, probably being one of the lesions responsible for extrapyramidal signs. In the generalized variant of Pick's disease, the degree and distribution of the alterations within the basal ganglia differs from those reported in Pick's disease with Pick bodies (PDPB) and corticobasal degeneration (CBD). In PDPB, severe lesions are present in the amygdala with relative sparing of the substantia nigra, compatible with rare extrapyramidal signs in PDPB, while in CBD, severe lesions are found in the pallidum and substantia nigra. These clinicopathological findings may contribute not only to the elucidation of clinicopathological hallmarks, but also to the progress of neuroimaging, in the generalized variant of Pick's disease. [ABSTRACT FROM AUTHOR]

Double immunofluorescence for paired helical filament (PHF)-tau (AT8) and ubiquitin, enhanced by catalyzed reporter deposition amplification, was combined with thiazin red (TR), a fluorochrome, which has an affinity to fibrillary structures such as neurofibrillary tangles (NFTs). After recording these triple-fluorescent images, sections were subjected to the Gallyas silver impregnation method, so that four different staining properties could be compared on the same structure. Among pyramidal neurons quantified in the hippocampus from six cases of Alzheimer's disease, 60.3% were positive for ubiquitin, and were consistently positive for TR. TR-positive neurons (77.1%) harbored fibrillary structures in the cytoplasm and were always positive for the Gallyas stain, which stained the largest number of legions (94.5%). AT8-positive neurons without fibrillary structure were negative for TR (11.6%, pretangle neurons). Some of the pretangle neurons were positive for the Gallyas stain even without fibrillary structures. Appearance of TR stain and ubiquitin in NFTs, but not in pretangle neurons, suggests that ubiquitin is integrated into tau-positive neurons after their transformation into NFTs. Because TR-positive NFTs sometimes lacked ubiquitin-like immunoreactivity, involvement of ubiquitin may not be an early event during NFT formation. This combined method is now found useful in determining how molecules other than tau are involved during the evolution from tau-positive neurons to NFTs in various neurological disorders characterized by the deposition of tau. [ABSTRACT FROM AUTHOR]

Thiazin red (TR), a fluorochrome that has an affinity to fibrillary structures such as neurofibrillary tangles (NFTs) or senile plaques, was utilized to investigate assembly of tau protein into fibrils in tau-immunopositive neocortical neurons of corticobasal degeneration (CBD) and of Alzheimer’s disease (AD). Double fluorescence with anti-paired helical filament monoclonal antibody (AT8) and TR was followed by either the Gallyas or Bodian silver impregnation method, which enabled a comparison of the staining features by three different methods on the same neuron. NFTs of AD were uniformly stained by TR and Gallyas method. Most of tau-immunopositive neurons of CBD were similarly stained by Gallyas method but barely or only weakly by TR or Bodian method, suggesting that tau in neocortical neurons of CBD is less liable to form fibrillary structures than in those of AD, easily distinguishable by TR staining. Clarifying the process of tau assembly using this fluorochrome will give a clue to understanding mechanisms of tau deposition, which may be different in various neurological disorders. [ABSTRACT FROM AUTHOR]

We investigated immunohistologically the Golgi apparatus (GA) and the trans-Golgi network (TGN) of the cortical ballooned neurons (BNs) in two patients with corticobasal degeneration and in five with Creutzfeldt-Jakob disease. We observed that the BNs showed fragmentation of the GA and the TGN, accompanied by a reduction in the number of fragmented Golgi elements and by a unique perinuclear distribution. This is the first report of the abnormalities of GA in cortical BNs. These findings suggests that the GA and the TGN may play some roles in the BN formation. [ABSTRACT FROM AUTHOR]

To resolve the controversy regarding the involvement of the dentate nucleus in corticobasal degeneration (CBD), an entire profile of the dentate nucleus was exposed in a sagittal plane and divided into four fields, and the number of neurons in each filed was counted separately using a computer-assisted analyzer in five cases of CBD and compared to those from seven age-matched controls. The size of the nucleus and the number of neurons were significantly reduced in all five cases of CBD. The neuronal loss had a definite regional predilection, more severe in the caudolateral neodentatum than in the rostromedial palaeodentatum, and was accompanied by grumose degeneration and astrogliosis which paralleled the severity of the neuronal loss. Thus, the dentate nucleus appears to be a cardinal target in CBD. [ABSTRACT FROM AUTHOR]

α-Synuclein is a presynaptic terminal protein that accumulates abnormally in plaques in Alzheimer’s disease (AD), in Lewy bodies in Lewy body disease (LBD) and in filamentous inclusions in multiple system atrophy. Since it has been previously shown that proteinase K or formic acid pretreatment enhances α-synuclein immunoreactivity in Lewy bodies and plaques, we hypothesized that the immunoreactivity in tangles, glial cells and Pick bodies might be revealed by such pretreatment. Brain sections from patients with AD, LBD, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick’s disease were pretreated with proteinase K or formic acid and immunostained with antibodies against the N-terminal, C-terminal or non-amyloid β component of AD amyloid (NAC) regions of α-synuclein. This study showed that after proteinase K (but not formic acid) pretreatment the anti-C terminus antibody immunostained neurofibrillary tangles of AD, PSP and CBD, and glial inclusions of PSP and CBD, as well as Pick bodies. Western blot analysis confirmed that in cases other than LBD, the anti-C terminus antibodies also recognized the native α-synuclein band and no cross-reactive bands were observed. In contrast, in LBD, after formic acid pretreatment with the anti-NAC antibody astroglial cells and granular neurons were immunostained. The N-terminal region antibody only recognized the lesions in LBD cases and not those of other neurodegenerative disorders. These results support the view that different fragments of α-synuclein might play an important role in the pathogenesis of several neurodegenerative disorders. [ABSTRACT FROM AUTHOR]