Acta Neuropathologica最新文献

Lobar intracerebral haemorrhage (ICH) is associated with cerebral amyloid angiopathy (CAA) pathology. Uncertainty remains about the mechanisms leading from CAA to ICH. We investigated the distribution and characteristics of CAA, and its clinical and neuropathological associations. Participants underwent research autopsy in the Lothian IntraCerebral Haemorrhage, Pathology, Imaging and Neurological Outcome (LINCHPIN) study. Neuropathologists rated tissue for CAA using standardised consensus criteria, as well as non-amyloid small vessel disease, Thal phase, and Braak stage. We compared the presence, distribution, and severity of CAA among different brain regions, and in the lobe or hemisphere affected by lobar ICH to corresponding contralateral regions. We evaluated the diagnostic accuracy of Vonsattel CAA grade on a post-mortem cortical specimen (simulating surgical biopsy) versus the reference standard of moderate-to-severe parenchymal CAA at autopsy. Among 162 participants, parenchymal CAA, meningeal CAA, and CAA-associated vasculopathy were diffusely distributed among all cerebral lobes irrespective of the ICH location, but capillary CAA showed an occipital predominance. In lobar ICH, all CAA measures did not differ between the ICH lobe or hemisphere and the contralateral unaffected region. CAA measures did not increase with age, but they were higher in carriers of APOE ε2 or ε4 alleles and in individuals with higher Thal phase or Braak stage. Using a rule-out category of Vonsattel grade ≥ 1 to diagnose CAA on a simulated cortical biopsy achieved 100% sensitivity (95%CI 93.4–100), and a rule-in category of Vonsattel grade ≥ 2 had 79.5% specificity (95%CI 63.5–90.7) versus the reference standard. The distribution and severity of parenchymal CAA, meningeal CAA, and CAA-associated vasculopathy are diffuse regardless of ICH location, indicating the need to better understand the factors underlying bleeding in CAA-affected vessels.

Alzheimer’s disease (AD) is phenotypically characterised by progressive memory loss, which has been linked to tau aggregation and synaptic dysfunction. Here we characterised the nanoscopic tau aggregates in individual synaptosomes from AD cases and controls, measuring their number and size using SynPull with direct stochastic optical reconstruction microscopy (dSTORM). A total of 7888 synaptosomes from pre-frontal cortex samples were studied, showing the presence of AT8-positive tau aggregates in a small fraction of synaptosomes (~ 3%) from control brains, reaching ~ 20% by Braak stage 6. These key findings of the intra-synaptic localisation of aggregates and existence of synaptic tau pathology at Braak stage 3—preceding tangle formation in this region, were confirmed using aggregate-specific single-molecule array (SIMOA) with proteinase K digestion, three-dimensional super-resolution microscopy, stimulated emission depletion microscopy (STED), and immunohistochemistry. The aggregates also grew in size with AD progression with an average length of 117 nm at stage 0, 154 nm at stage 3 and 182 nm at stage 6, however they mostly remained non-elongated (circular) with average eccentricity values remaining below 0.8. We then investigated the multi-phosphorylation of synaptic tau aggregates for AT8 and T181 and quantified their co-localisation with phosphatidylserine and CD47, synaptic “eat me” and “don’t eat me” signals respectively, along with synaptogyrin-3, which contributes to tau-mediated synaptic dysfunction. T181, phosphatidylserine, and synaptogyrin-3 co-localisation with AT8-positive tau were higher during stage 3 and CD47 was lower, indicating early synaptic pathology is associated with the formation of small tau aggregates, contributing to microglia-driven synaptic loss.

Familial occurrence of gliomas has been reported in around 5% of patients. Studies on the genetic landscape of glioma predisposition are scarce. Here, leukocyte DNA of 213 adult glioma patients with a familial and/or personal tumor history from 206 families was subjected to whole-exome sequencing. Germline variants (GVs) were analyzed using two approaches: (1) GVs in 164 established cancer predisposition genes (CPGs) or suspected glioma risk genes were extracted and classified; (2) the enrichment of genes with loss-of-function or deleterious missense GVs that were ultrarare or ClinVar likely pathogenic/pathogenic in the glioma versus a control cohort (n = 391) was determined. In 23% (48/213) of glioma patients with a familial/personal tumor history, GVs predicted to be deleterious in CPGs were detected. Of the mutated CPGs, 37% were involved in DNA damage response, including ATM, BRCA2, PMS2, POLE. ATM GVs (n = 6) preferentially predisposed to IDH-mutant astrocytoma (P = 0.007) in patients that were significantly younger at diagnosis than patients without GVs (P = 0.022). BRCA2 GVs (n = 5) were also significantly enriched in glioma patients in approach 2 (P = 0.005). The other mutated CPGs, glioma risk or enriched novel genes play roles in diverse processes, including metabolism and signal transduction. Syn-/metachronous non-brain tumors were diagnosed in 29% of glioma patients with GVs. In 11% of patients, the identified CPG GVs potentially sensitized to targeted therapies, such as PARP, immune checkpoint, or EGFR inhibitors. In conclusion, our study identifies CPGs and novel genes relevant in germline testing of glioma patients with a familial/personal tumor history, possibly resulting in targeted treatment options.

Creutzfeldt-Jakob disease (CJD), the most common human prion disease, is an invariably fatal neurodegenerative disorder affecting 1.5 cases per million individuals per year. About 10–15% of the human prion diseases are caused by a pathogenic variant in the prion protein (PrP) gene (PRNP), and the most common genetic human prion disease is CJD (gCJD) linked to a glutamic acid to lysine substitution at codon 200 (E200K) of PRNP. The polymorphic codon 129 methionine (M)/valine (V) genotype has a strong effect on disease phenotype. In the present study, we retrospectively evaluated many features of gCJD E200K cases with respect to the 129MV polymorphism, type of scrapie prion protein (PrP^Sc), demographic, clinical, laboratory, histopathology, and molecular features, including western blot examination and real-time quaking-induced conversion assay. Analyses were also performed to determine statistically significant features between E200K haplotypes (e.g., codon 129 genotype in cis with the mutated allele) and codon 129 genotypes. This study found that codon 129 polymorphism affects several disease features of gCJD E200K. Specifically, histopathologic differences were found between patients with different 129 haplotypes and genotypes. We have identified five groups or subtypes of E200K associated with either PrP^Sc type 1 or 2. Other E200K cases showed mixed (i) PrP^Sc types or (ii) pathological features of 129 M and 129 V haplotypes. To our knowledge, this study describes the largest cohort of 177 E200K cases and provides new insight into the wide range of phenotypes associated with this common CJD genetic variant.

Synucleinopathies, including Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), share pathological accumulation of misfolded α-synuclein (αSyn) in the brain and overlapping clinical features, complicating accurate diagnosis with current methods. In this study, we utilized a real-time quaking-induced conversion (RT-QuIC) assay to demonstrate that autopsied skin samples from PD, DLB, and MSA patients (but not non-synucleinopathy controls) seed aggregation of recombinant αSyn. While RT-QuIC generated similarly positive fluorescence kinetic curves across synucleinopathies, biochemical and morphological analyses of RT-QuIC end products revealed distinct properties in the resulting αSyn aggregates. Notably, αSyn aggregates from DLB samples exhibited the highest resistance to proteinase K digestion, whereas MSA-derived aggregates showed the least aggregated bands on Western blots. Transmission electron microscopy revealed significant differences in length, width, and volume of skin αSyn fibrils of RT-QuIC end products from different synucleinopathies. These findings provide critical insights into disease-specific αSyn structural characteristics and suggest new strategies to improve diagnostic discrimination.

Essential tremor (ET), among the most common movement disorders, is characterized by 8–12 Hz action tremor of the upper extremities. Cognitive dysfunction is increasingly recognized. Postmortem studies of anterior cerebellar cortex, which plays a major role in motor function, have systematically identified morphologic changes centered on Purkinje cells (PCs) and adjacent neuronal connections, distinguishing ET from controls. However, the cerebellar cortex is compartmentalized into distinct functional anatomic regions, including control of cognition in posterior lobe. No systematic study of this posterior region has been undertaken in ET. Leveraging resources of the Essential Tremor Centralized Brain Repository, we compared the pathology across anterior and posterior hemispheric cerebellar cortices in each brain in a postmortem series of 123 brains in ET (n = 80) and controls (n = 43). We used 11 quantitative morphologic metrics that reflected PC loss, heterotopic PCs, PC dendritic changes, PC axonal changes (torpedoes, torpedo-associated and non-torpedo related), basket cell axonal hypertrophy, and climbing fiber-PC puncta changes. These metrics distinguished ET cases from controls in both anterior (11/11 metrics) and posterior regions (10/11 metrics) (p values 0.045 to < 0.0001), and 10/11 metrics demonstrated a greater burden of pathology in the ET anterior versus ET posterior cerebellar region (p values 0.045 to < 0.0001). Regional differences among controls were present to a lesser extent than in ET (6/11 metrics; p values 0.035 to < 0.0001). In a principal component analysis, these combined metrics segregated control and ET cases according to both diagnosis and cerebellar region. This is the first study to carefully document that pathology in the ET cerebellum extends beyond the anterior cerebellar region to also involve a posterior cerebellar region. In line with the prominent motor features of ET, the burden of cerebellar pathology was greater in the anterior region. These results advance our nascent understanding of the underlying neuropathological substrate of this highly prevalent disease.

Vasculitic myopathy (VM) represents a nonspecific manifestation of various vasculitic syndromes that presents with myalgia, leg tenderness, and muscle weakness. Most cases of VM develop in the context of polyarteritis nodosa (PAN), antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, or rheumatoid vasculitis, or manifest as single organ vasculitis. Muscle inflammation in VM is poorly understood, and most studies essentially report the presence of vasculitic changes demonstrated by microscopic analysis of skeletal muscle tissue. However, no detailed characterization or in-depth analyses have been performed so far. We studied the clinicopathologic phenotype of 12 patients and analyzed the gene expression profiles of 36 patients with VM in the context of negative ANCA test results. ANCA-negative VM typically presents with myalgia involving the lower extremities, accompanied by cutaneous manifestations, constitutional symptoms, and marked systemic inflammation. Half of the patients (6/12; 50.0%) met the classification criteria for ‘classic PAN’. Serum creatine kinase (CK) activity was normal in most cases (10/12; 83.3%). The presence of skeletal muscle vasculitis was confirmed by histopathology in 9/12 (75.0%) cases. Specifically, ANCA-negative VM predominantly affected small arteries and was consistently associated with small vessel involvement of the epimysial fascia (9/10; 90.0%), which was termed ‘vasculitic fasciitis’ (VF). Signs of necrotizing vasculitis were occasionally noted (3/9; 33.3%). Mild endomysial fibrosis and muscle fiber necrosis could be compatible with a rather acute disease onset and may account for normal or slightly elevated levels of serum CK activity, respectively. Additionally, nonspecific myopathic changes such as capillary vessel mural thickening and variations of muscle fiber size were detected in all analyzed muscle biopsy specimens. Immunohistochemical studies revealed perifocal sarcolemmal upregulation of major histocompatibility complex class I in the majority of cases (10/11; 90.9%). RNA sequencing of muscle biopsies from 36 ANCA-negative VM patients, compared to 37 healthy controls and 649 samples from other inflammatory myopathies, revealed that ANCA-negative VM is characterized by a dominant interferon-gamma-driven immune response, broad cytokine activation including tumor necrosis factor-related genes, and selective upregulation of angiogenesis- and endothelium-associated transcripts. Our histomorphologic analysis highlights a distinct histopathological pattern of VF that is characteristic for muscle involvement in ANCA-negative vasculitis. Furthermore, we provide evidence for a specific molecular signature that gives new insights into the pathogenesis and treatment of ANCA-negative VM.

To advance the nosology of pathologic Parkinson’s disease (PD), we examined the associations of Lewy bodies (LBs), nigral neuronal loss (NNL), and co-pathologies with cognitive decline and progression of parkinsonian signs in older decedents without clinical PD during life. Nineteen cognitive tests and 26 Unified Parkinson’s Disease Rating Scale items were measured annually. We measured both elements of pathologic PD, i.e., LBs and NNL, and eight other Alzheimer’s disease and related dementias (ADRD) co-pathologies in 1717 brains. A semiquantitative scale (0–3) was used to assess NNL. Pathologic PD was based on the presence of LBs plus moderate or severe NNL. Possible pathologic PD was based on LBs alone or LBs with mild NNL. A series of bivariate linear mixed effect models jointly quantified cognitive decline and progressive parkinsonian signs in each decedent. Almost 30% of decedents without a diagnosis of clinical PD showed elements of pathologic PD [pathologic PD (8%); possible pathologic PD (19%)]. On average, pathologic PD accounted for 4.9% of the variance of cognitive decline and 9.4% of the variance of progression of parkinsonian signs controlling for ADRD pathologies. Adding another term for possible pathologic PD accounted for an additional 1.8% variance of cognitive decline but did not account for additional variance of progressive parkinsonian signs. Co-pathologies accounted for an additional 19% of cognitive decline and 7% of progressive parkinsonism. Thirty-three percent of the association of LBs with cognitive decline was attributable to NNL. In contrast, more than 70% of its association with progressive parkinsonism was attributable to NNL. Subclinical pathologic PD in older adults is heterogeneous. The associations of LBs with cognition and parkinsonism may vary with the severity of NNL and together with its co-pathologies account for a minority of late-life progressive parkinsonism and cognitive decline. Synucleinopathies in older adults without clinical PD may be underestimated.