Neuropathology and Applied Neurobiology最新文献

Aims: Evidence suggests Alzheimer's disease (AD) patients are at increased risk of epilepsy and that seizure incidence is associated with faster cognitive decline. Previous studies indicate hyperphosphorylated tau may play a role in this disease association; however, abnormal TDP-43 and α-synuclein deposition have not been extensively examined.

Methods: Clinical and neuropathological records of AD cases over a 5-year period were retrieved from the London Neurodegenerative Diseases Brain Bank. The 114 cases were categorised into three groups: AD plus epilepsy, AD plus hippocampal sclerosis (HS) and AD only. Semi-quantitative scores for tau, TDP-43 and α-synuclein pathology within the middle temporal gyrus, hippocampus and amygdala were compared between groups.

Results: A 12% incidence of epilepsy and/or epileptic symptomology was found among the cohort. Twelve cases (11%) showed HS. No significant difference in tau pathology scores was seen between groups. However, a significantly higher score for TDP-43 was seen in AD plus epilepsy compared with AD only in the middle temporal gyrus (p = 0.004). The burden of α-synuclein pathology was increased in the amygdala of AD plus epilepsy and AD plus HS.

Conclusions: The incidence of epilepsy within this AD cohort is higher than expected within the general population (even when matched for age), and this may be associated with increased TDP-43 burden. Understanding the relationship between AD and epilepsy may highlight mechanisms of cellular damage and tissue vulnerability.

We report an infantile spinal tumour with diffuse leptomeningeal dissemination and features of a glioma with CUX1::RAF1 fusion and the DNA-methylation class, infant-type hemispheric glioma. This strange case was similar to a previously reported tumour reported in the literature, which clustered perfectly with our case. Further reports are needed to confirm the hypothesis that this neoplasm represents a novel tumour type.

Aims: Enterovirus A71 (EV-A71) can cause fatal encephalomyelitis, but the mechanisms of its spread within the central nervous system (CNS) remain unclear. This study aimed to investigate the pathways of EV-A71 dissemination after direct intracerebral inoculation and to assess the role of the murine Scavenger Receptor Class B Member 2 (mSCARB2) receptor in this process.

Methods: A mouse-adapted EV-A71 strain (MAVS) was intracerebrally inoculated into the thalamus/hypothalamus or pons/medulla of 2-week-old ICR mice. Tissues were harvested and analysed by histopathology and viral titration at 24, 48 and 72 h post-infection (hpi). The infectivity of MAVS was also tested on N1E115 mouse neuroblastoma cells.

Results: Viral antigens at the injection sites diminished over time, with restricted centrifugal inter-neuronal spread. From 48 hpi, viral antigens increased in distant motor-related neurons of the brainstem and spinal cord. There was a poor correlation between mSCARB2 expression and sites of infection; despite high mSCARB2 expression in the brain, spread was limited, while skeletal muscle, which lacks mSCARB2, showed severe infection. Direct infection of N1E115 cells was inefficient, but viral RNA transfection resulted in robust replication.

Conclusions: The findings suggest a circuitous dissemination route: viral leakage from the CNS leads to viraemia and peripheral muscle infection, followed by retrograde axonal transport back into the brainstem and spinal cord. This pathway appears to be the dominant mode of CNS invasion, independent of mSCARB2 distribution. Alternative receptor pathways likely play a critical role in EV-A71 neuropathogenesis.

We employed a novel method for collecting oral mucosal epithelial cells, an anagar-paraffin double-embedding technique for cell fixation in cytopathological processing. OMEC biopsy demonstrated a high diagnostic efficacy for NIID: H&E staining revealed inclusions in 60% (12/20) of patients, TEM confirmed them in 40% (8/20) of cases and immunofluorescence detected p62-positive aggregates in 9/20 (45%) and uN2CpolyG in 8/20 (40%) of cases, respectively. OMEC biopsy is a simple, noninvasive technique for detecting intranuclear inclusions in NIID, avoiding the need for invasive surgical procedures such as skin or labial gland biopsies.

Aims: This study aims to develop a quantitative method for assessing collagen VI expression in cell cultures, which is crucial for the diagnosis and treatment of collagen VI-related dystrophies.

Methods: We developed a combined in-cell western (ICW) and on-cell western (OCW) assay, which we have called 'collablot', to quantify collagen VI and its organisation in the extracellular matrix of cell cultures from patients and healthy controls. To optimise it, we optimised cell density and the protocols to induce collagen expression in cultures, as well as the cell fixation and permeabilisation methods. This was completed with a thorough selection of collagen antibodies and a collagen-hybridising peptide (CHP). We then used collablots to compare cultures from patients and controls and evaluate therapeutic interventions in the cultures.

Results: Collablots enabled the quantification of collagen VI expression in both control and patient cells, aligning with immunocytochemistry findings and detecting variations in collagen VI expression following treatment of the cultures. Additionally, CHP analysis revealed a marked increase in collagen network disruption in patients compared to the controls.

Conclusions: The collablot assay represents a suitable method for quantifying collagen VI expression and its organisation in culture and assessing the effect of therapies.

Aims: Diagnosis of inclusion body myositis (IBM) is difficult and currently based on a combination of clinical and (immuno)histological findings. Biomarkers facilitating the diagnostic process are needed. Alpha-synuclein (αSN) aggregates are a known histological feature of IBM, but there is a lack of information on their diagnostic relevance. Furthermore, serum αSN concentrations in IBM have not been investigated.

Methods: Immunohistochemical staining for αSN was performed on 63 biopsies (19 IBM, 21 other inflammatory myopathies, 20 other myopathies and 3 healthy controls), and αSN reactive fibres were quantified. The serum concentration of αSN was determined by ELISA in 156 serum samples (11 IBM, 25 other inflammatory myopathies, 53 hereditary myopathies, 30 mitochondriopathies and 37 healthy controls).

Results: The proportion of fibres with αSN immunoreactivity was significantly higher in IBM compared to all groups (p < 0.001) and discriminated IBM against all other neuromuscular disorders with a sensitivity of 79% and a specificity of 85%, which further improved when only non-regenerating fibres were examined. In serum, αSN concentrations in IBM were generally not different from healthy controls. However, serum concentrations were inversely correlated with disease duration (r = -0.62, p = 0.04) and positively correlated with the IBM functional rating scale (r = 0.74, p = 0.01). Consequently, stratification according to these clinical parameters showed significantly lower serum αSN concentrations in late-stage, more severely affected patients.

Conclusions: αSN reactivity may serve as an additional immunohistochemical marker for IBM diagnosis. Furthermore, this study indicates that αSN serum concentrations decrease with disease duration and clinical deterioration. Therefore, serum αSN may be provisionally considered a monitoring biomarker in IBM, pending further studies.

In the study, we employ an affordable, tissue-saving, and precise simultaneous multiplex immunofluorescence method with heat-induced antibody stripping to identify and structurally analyse nigral Lewy bodies in dopaminergic neurones. Analysis of different alpha-synuclein epitopes and proteoforms reveals an almost uniform, onion-like morphology of the Lewy bodies. The N-terminal and C-terminal domains are predominantly accessible to antibody binding in the peripheral shell of the bodies.

Congenital myopathies and congenital muscular dystrophies encompass heterogeneous clinical and genetic groups of disorders characterised by muscle weakness with antenatal or early postnatal onset. These conditions are categorised according to distinctive myopathological features and causative genes. Despite advances in diagnosis through massive parallel sequencing and progress in understanding the underlying pathogenesis, many aspects of these disorders remain poorly understood. MYL1-related congenital myopathy is an ultra-rare and severe condition, associated with a deficiency of essential/alkali light myosin and impaired development of fast-twitch type II muscle fibres. This study aims to advance the understanding of the phenotype and pathogenesis of MYL1-congenital myopathy. We analysed the clinical characteristics of two individuals harbouring three novel variants in the MYL1 gene. We conducted detailed genomic analysis and extensive studies on their muscles using histological, immunohistochemical, immunofluorescence, Western Blot and electron microscopy. Both individuals showed a very severe congenital myopathy, characterised by congenital hypotonia and weakness, requiring ventilatory and nutritional assistance. Muscle biopsy revealed dystrophic-like or myopathic changes, with notable smallness of fast-twitch type II fibres, often arranged around larger type I fibres, drawing a floret pattern. These fibres expressed developmental myosin and exhibited features of aberrant myofibrillogenesis. Type I myofibres exhibited correct sarcomere alignment, but like the small fast-twitch fibres, both showed distorted cell organelles, vacuolar aggregates and membranous debris, indicating autophagic impairment. Our findings confirm that bi-allelic MYL1 variants are associated with a severe congenital myopathy, characterised by a distinctive clinical and histopathological phenotype involving impaired type II fibre development. Additionally, our study reveals a role for MYL1 in the organisation and trophism of all muscle fibre types. SUMMARY: MYL1 biallelic variants cause severe congenital myopathy with early hypotonia and type II fibre hypotrophy. Muscle biopsy shows a distinct pattern, including floret-like fibre arrangement. Findings suggest a broader role for MYL1 in fibre organisation and autophagy across muscle fibre types.

Aims: Lecanemab, an Alzheimer's disease US Food and Drug Administration-approved monoclonal antibody, was previously reported to have a high affinity against intermediately sized amyloid-β aggregates. Subsequently, it was observed by immunogold labelling that lecanemab can also bind to human type I amyloid-β fibrils. To determine whether lecanemab binds to amyloid-β fibril structures other than type I, we analysed its binding capacity to various structurally defined and pathologically relevant amyloid-β fibrils.

Methods: We performed immunogold labelling with lecanemab on extracted amyloid-β fibril preparations from six different Alzheimer´s disease mouse models whose structures were previously solved by cryo-EM and quantified the relative binding affinities of lecanemab to the different fibril polymorphs.

Results: Our results show that lecanemab exhibits high binding affinity to amyloid-β fibril structures that have a flexible N-terminus in common, as is the case for type I, type II and murine type III amyloid-β fibril polymorphs, which resemble or are identical to human structures observed in sporadic and familial cases of Alzheimer's disease, including a case with the Arctic (E22G) mutation. In contrast, only weak lecanemab binding was observed for murine amyloid-β fibrils with a fixed and ordered N-terminus.

Conclusions: These findings may also explain the low incidence of ARIA-E with lecanemab in clinical trials. This is because human meningeal amyloid-β fibrils derived from cerebral amyloid angiopathy affected brain tissue also contain a fixed and ordered N-terminus, most likely preventing lecanemab binding.

Summary: Lecanemab binds to Aβ fibrils from several Alzheimer's disease tg-mice whose structures resemble the type I, type II and Arctic folds found in Alzheimer's patients, all of which share a flexible, unstructured N-terminus. Lecanemab is therefore expected to be active against all common familial and sporadic Alzheimer's cases containing these folds. Lecanemab binding ability is unaffected by and tolerates the Arctic E22G mutation, at least in type I or Arctic folds. Only weak, if any, lecanemab binding was observed to Aβ fibrils derived from tg-SwDI mice, whose structures DI1, DI2 and DI3 all share structured and fixed N-termini. Since the fixed N-termini of tg-SwDI DI1 fibrils and human meningeal Aβ40 fibrils derived from CAA-affected brain are identical, most likely preventing lecanemab binding, treatment with lecanemab may be less effective or ineffective against CAA, but may explain the reported beneficial low ARIA-E frequency with this antibody.

Aims: To identify potential image biomarkers of neuromuscular disease by analysing morphological and network-derived features in skeletal muscle biopsies from a murine model of amyotrophic lateral sclerosis (ALS), the SOD1^G93A mouse and wild-type (WT) controls at distinct stages of disease progression.

Methods: Using the NDICIA computational framework, we quantitatively evaluated histological differences between skeletal muscle biopsies from SOD1^G93A and WT mice. The process involved the selection of a subset of features revealing these differences. A subset of discriminative features was selected to characterise these differences, and their temporal dynamics were assessed across disease stages.

Results: Our findings demonstrate that muscle pathology in the mutant model evolves from early alterations in muscle fibre arrangement, detectable at the presymptomatic stage through graph theory features, to the subsequent development of the typical morphological pattern of neurogenic atrophy at more advanced disease stages.

Conclusions: Our assay identifies a neurogenic signature in mutant muscle biopsies, even when the disease is phenotypically imperceptible.