Journal of Neuropathology and Experimental Neurology最新文献

Cerebral small vessel disease (CSVD) is a major cause of stroke and dementia yet its mechanisms remain poorly understood due to the lack of reliable animal models. This study aimed to develop a novel rat model that replicates human CSVD pathology by combining a 2-kidney 2-clip hypertensive procedure with a high-salt diet. High-salt diet stroke-prone renovascular hypertensive (RHRsp) rats exhibited sustained hypertension, cerebral small artery remodeling, cognitive impairments, and lacunar infarcts, closely mimicking human sporadic CSVD. This model overcomes limitations of existing approaches by accelerating pathological changes and providing a comprehensive representation of CSVD features. The results demonstrate that the high-salt diet RHRsp rat is a promising model for studying hypertension-associated CSVD, offering a robust platform for investigating disease mechanisms and testing therapeutic interventions. This advancement enhances our understanding of CSVD pathology and supports the development of targeted treatments.

Calcium pyrophosphate deposition (CPPD) disease is an inflammatory arthritis prevalent in elderly individuals. Spinal CPPD is uncommon, and presentation can vary widely with common clinical and radiographic mimics. We identified 9 cases of lumbar and 1 case of thoracic spinal CPPD (age range: 63-85 years; 5 male, 5 female) at our institution over a 10-year period. All presented with pain (90% chronic, 10% acute); 4 had prior instrumentation and 1 had prior trauma. CPPD was not clinically suspected in any case. Preoperative imaging diagnoses include central canal stenosis, neuroforaminal narrowing, septic arthropathy, synovial cyst, degeneration, and epidural mass/abscess. Intraoperatively, a spinal cyst was most often described. All pathologic examinations revealed purple granular calcified material with positively birefringent rhomboid crystals embedded within fibrocartilage. Following a neuropathologic diagnosis, only 2 patients received CPPD treatment. This study aims to highlight that spinal CPPD is underdiagnosed and undertreated. Although clinical presentations are variable, wider recognition of this rare disease among neuropathologists receiving spinal specimens may provide earlier diagnosis. Accurate pathologic diagnosis can improve identification, refine clinical suspicion, and facilitate management. Improved identification, particularly in elderly patients and those with prior trauma/instrumentation, will promote appropriate therapy and management.

In the absence of molecular biomarkers, the current diagnosis of multiple sclerosis is based on clinical assessment, neuroimaging, and detection of oligoclonal bands in cerebrospinal fluid. Early and rapid diagnosis using patient samples obtained by non-invasive methods would be a major advance in clinical management. We tested 5 different methods for preparation of the plasma proteome for liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. These were as follows: (1) single-pot, solid-phase-enhanced sample preparation (SP3), (2) iST and (3) ENRICH-iST of raw plasma, (4) SP3 of highly abundant-proteins depleted plasma (DEPL-SP3), and (5) SP3 of plasma extracellular vesicles (EV-SP3). DEPL-SP3 and EV-SP3 sample preparation workflows yielded the highest numbers of quantified plasma proteins. Using both methods, we analyzed the plasma proteome of 15 relapsing-remitting multiple sclerosis (RRMS) patients and 5 healthy controls. We found 54 and 35 regulated plasma proteins with DEPL-SP3 and EV-SP3 workflows, respectively. Among them, von Villebrand factor (VWF) was identified as a potential RRMS diagnostic biomarker. The use of sample preparation workflows for LC-MS/MS analysis that describe both the soluble and EV plasma proteomes might increase the likelihood of identifying new and robust RRMS biomarkers.

The aggregation of amyloid-β (Aβ) and phosphorylated tau (p-tau) in the human brain is associated with Alzheimer disease (AD). Although Aβ aggregation has been reported in various mammals, significant p-tau aggregation has been reported in only a few species. We examined Aβ and p-tau aggregation in the brains of 30 animals belonging to 12 artiodactyl species. Amyloid-β aggregates were observed in 2 animals (21 and 22 years old); p-tau aggregates were observed in all animals >9 years of age (n = 12). Regarding tau pathology, mildly affected animals exhibited neuropil threads (NTs), whereas severely affected animals exhibited NTs and neurofibrillary tangles. The most severe p-tau aggregation was observed in the parahippocampal gyrus, basal ganglia, hippocampus, and cerebral cortex. Proteinase K treatment resulted in high proteinase resistance for 4-repeat tau and low resistance for 3-repeat tau. These results suggest that p-tau aggregation occurs prior to Aβ aggregation in artiodactyls, which differs from other mammalian species and human AD. Regarding the distribution, p-tau aggregated in neurites and then in the neuronal cell soma of the parahippocampal gyrus and spread to associated regions of the brain. Moreover, 4-repeat tau was the main component of proteinase-resistant p-tau aggregates in the artiodactyl brains studied.

Cystatin C (CST3) colocalizes with amyloid-β (Aβ) around vessels in cerebral amyloid angiopathy (CAA). This study aimed to characterize CST3-Aβ interactions in CAA. Brain tissues from 12 Alzheimer disease (AD) and 5 non-AD control subjects, along with AD model mice (J20), were examined. In AD brains, immunohistochemistry revealed Aβ positivity around cortical and leptomeningeal vessels as well as in intra- and extracellular areas. Congo red-positive vessels were also present. Conversely, control brains showed only few Aβ-positive cells. CST3 was primarily intracellular in controls, but in AD, it was found both to be intracellular and perivascular, colocalizing with Aβ and Congo red in affected vessels. Vessel quantification showed a positive correlation between CST3-positive and Aβ- or Congo red-positive vessels. Moreover, most CST3-positive vessels were Cathepsin B (CatB)-negative. CatB was significantly decreased in AD and inversely correlated with CAA severity. Immunoprecipitation followed by Western blotting, dot blot, and TEM revealed oligomeric aggregates and short fibrillar CST3 bound to Aβ in both AD and J20 mice brains. In J20 mice, CST3 was only neuron-positive at 2 months, and vessel-positive, colocalizing with Aβ from 3 months. These findings suggest that aggregated CST3 binds to Aβ and accumulates around vessels, potentially contributing to CAA pathogenesis.

Theiler's murine encephalomyelitis virus (TMEV) infection in mice has been used to study diverse neurological diseases, including multiple sclerosis and epilepsy. In this investigation, 5 strains of collaborative cross (CC) mice were infected with TMEV and examined clinically and histologically at days 4, 14, and 90 post-infection (dpi). All CC strains tested exhibited lumbar spinal cord and/or ventral peripheral nerve lesions by 14 dpi; CC027, CC023, and CC078 strains exhibited lesions at 4 dpi. At 90 dpi, lesions were remnants of the inflammatory responses associated with earlier infection; there was skeletal muscle atrophy in the CC023 strain. Increased microglial/macrophage reactivity was observed in all strains at 4 and 14 dpi, but not at 90 dpi. TMEV mRNA expression was greatest in the CC023 and CC078 strains at the acute timepoints; TMEV was completely cleared in all mice at 90 dpi. The neuropathological and clinical profiles in CC023 mice, mainly at 14 dpi, share some clinical and histologic features with those in amyotrophic lateral sclerosis patients. This work demonstrates how viral infection might interact with the genetic background of a susceptible individual to contribute to the onset, clinical presentation and persistence of lesions despite viral clearance.

Mitochondria are critical for cellular function. Their dysfunction contributes to cell degeneration and death, leading to disease progression. This study examined mitochondrial changes in idiopathic inflammatory myopathies (IIMs) including antisynthetase syndrome (ASyS), dermatomyositis (DM), and inclusion body myositis (IBM). Skeletal muscle biopsies were analyzed using histology, histochemistry, and electron microscopy from patients diagnosed with IIMs, according to the clinico-sero-morphological classification. There was no significant age difference between 16 ASyS and 16 DM patients, but 11 IBM patients were significantly older. The ASyS group had higher serum creatine kinase levels and showed prominent mitochondrial abnormalities similar to IBM and greater than the DM group. While all IIM groups displayed conventional mitochondrial changes, including ultrastructural abnormalities with cristae alterations, paracrystalline inclusions were exclusive to IBM and ASyS. There were significantly more rod-like filamentous inclusions adjacent to mitochondria in the IBM and ASyS groups, compared to the DM group. Intra-mitochondrial filament aggregates with focal formation of inclusions were also identified in individual ASyS and IBM patients, suggesting a link between the mitochondrial filamentous inclusions and nuclear and/or cytoplasmic filamentous inclusions. These findings suggest that mitochondrial abnormalities, particularly in ASyS and IBM, may contribute to the pathogenic process and clinical manifestations of the disease.