Voxel‐based specific regional analysis system for Alzheimer’s disease utility as a screening tool for unrecognized cognitive dysfunction of elderly patients in diabetes outpatient clinics: Multicenter retrospective exploratory study

AIMS/INTRODUCTION: An efficient screening strategy for identification of cognitive dysfunction remains a clinical issue in the management of elderly adults with diabetes. A magnetic resonance imaging voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) has been developed as an automated brain morphometry system that includes the hippocampus. We carried out a multicenter retrospective study to evaluate the utility of VSRAD for screening cognitive dysfunction in diabetes outpatient clinics. MATERIALS AND METHODS: We enrolled patients with diabetes aged >65 years who underwent brain magnetic resonance imaging scans for the purpose of a medical checkup between November 2018 and May 2019. Patients who were already suspected or diagnosed with mild cognitive impairment and/or dementia as well as those with a history of cerebrovascular disease were excluded. RESULTS: A total of 67 patients were enrolled. Five patients were diagnosed with mild cognitive impairment or dementia (clinical cognitive dysfunction). Patients with clinical cognitive dysfunction showed a significantly higher z-score in VSRAD analysis (2.57 ± 0.47 vs 1.15 ± 0.55, P < 0.01). The sensitivities and specificities for diagnosis of clinical cognitive dysfunction were 80 and 48% for the Mini-Mental State Examination, 100 and 89% for the z-score, and 100 and 90% for the combination of the Mini-Mental State Examination score and z-score, respectively. CONCLUSIONS: VSRAD analysis can distinguish patients with clinical cognitive dysfunction in the elderly with diabetes, and also shows reasonable sensitivity and specificity compared with the Mini-Mental State Examination alone. Thus, VSRAD analysis can be useful for early identification of clinical cognitive dysfunction in the elderly with diabetes

Nasal Extracts from Patients with Alzheimer’s Disease Induce Tau Aggregates in a Cellular Model of Tau Propagation.

Background:Emerging evidence indicates that the misfolded tau protein can propagate aggregates between cells in a prion-like manner. This prion activity has been typically studied in brain extracts of patients with Alzheimer’s disease (AD), but not in the olfactory region that can be a potential biomarker in AD.Objective:To investigate the prion seeding activity of tau in nasal mucosa tissues using a cell culture model of tau propagation.Methods:Brain and nasal mucosa homogenates were added to HEK293T cells expressing three repeat or four-repeat domains of tau with the L266V, V337M (3RD*VM) and P301L and V377M mutations (4RD*LM) fused to the enhanced green fluorescence protein (EGFP) respectively. We also measured the level of phosphorylated tau (p-tau), total tau (t-tau), and p-tau/t-tau ratio and performed correlation analysis between tau prion activity and the level of tau.Results:We found that brain and nasal tissue homogenates from patients with AD significantly induced tau aggregation in HEK293T cells either expressing tau 3RD*VM-EGFP or 4RD*LM-EGFP compared with control brain and nasal tissue homogenates. The levels of p-tau and p-tau/t-tau ratio were significantly increased in the brain of patients with AD; however, no significant difference was found in nasal tissue compared with their respective control tissue homogenates.Conclusion:These results suggest that the nasal tissues contain tau seeds, similar to the brain, albeit without changes in the levels of p-tau and t-tau. Therefore, a cellular bioassay using nasal tissues would have great potential as an AD biomarker because of the usefulness of nasal tissue biopsy

Characterization of a Conformation-Restricted Amyloid β Peptide and Immunoreactivity of Its Antibody in Human AD brain.

Characterization of amyloid β (Aβ) oligomers, the transition species present prior to the formation of Aβ fibrils and that have cytotoxicity, has become one of the major topics in the investigations of Alzheimer\u27s disease (AD) pathogenesis. However, studying pathophysiological properties of Aβ oligomers is challenging due to the instability of these protein complexes in vitro. Here, we report that conformation-restricted Aβ42 with an intramolecular disulfide bond at positions 17 and 28 (SS-Aβ42) formed stable Aβ oligomers in vitro. Thioflavin T binding assays, nondenaturing gel electrophoresis, and morphological analyses revealed that SS-Aβ42 maintained oligomeric structure, whereas wild-type Aβ42 and the highly aggregative Aβ42 mutant with E22P substitution (E22P-Aβ42) formed Aβ fibrils. In agreement with these observations, SS-Aβ42 was more cytotoxic compared to the wild-type and E22P-Aβ42 in cell cultures. Furthermore, we developed a monoclonal antibody, designated TxCo-1, using the toxic conformation of SS-Aβ42 as immunogen. X-ray crystallography of the TxCo-1/SS-Aβ42 complex, enzyme immunoassay, and immunohistochemical studies confirmed the recognition site and specificity of TxCo-1 to SS-Aβ42. Immunohistochemistry with TxCo-1 antibody identified structures resembling senile plaques and vascular Aβ in brain samples of AD subjects. However, TxCo-1 immunoreactivity did not colocalize extensively with Aβ plaques identified with conventional Aβ antibodies. Together, these findings indicate that Aβ with a turn at positions 22 and 23, which is prone to form Aβ oligomers, could show strong cytotoxicity and accumulated in brains of AD subjects. The SS-Aβ42 and TxCo-1 antibody should facilitate understanding of the pathological role of Aβ with toxic conformation in AD

Carbohydrate Antigen 19-9-Positive Gastric Adenocarcinoma: Autopsy Findings and Review of the Literature

Carbohydrate antigen 19-9 (CA19-9) is a well-known tumor marker for pancreatobiliary cancer, and several studies have shown that an elevated serum CA19-9 level is associated with more aggressive biological behavior in gastric cancer (GC). However, the clinicopathological characteristics of CA19-9-positive GC remain unclear. We herein report an autopsy case of CA19-9-positive GC in an 84-year-old man who was admitted to our hospital because of paralysis and anemia. Autopsy revealed an ulcerative-invasive tumor measuring 72 × 60 mm in the anterior wall of the gastric body. The tumor had invaded beyond the muscularis propria, and metastasized to the lung, liver, and regional lymph nodes. Histologically, the tumor cell had oval nuclei with abundant clear cytoplasm, and tubular and/or papillary features with prominent lymphovascular permeation and perineural invasion, mimicking pancreatobiliary carcinoma. Immunohistochemically, the tumor cells showed diffuse immunopositivity for CA19-9 and carcinoembryonic antigen. According to a review of cases reported in the literature, CA19-9-positive GCs show clinicopathological characteristics such as antral location, ulcerative-infiltrating gross feature, differentiated histology, prominent lymphatic and venous invasion, higher proportion of metastasis, and higher clinical stage. These results suggest that CA19-9-positive GC is pathologically a distinctive type of tumor with aggressive biological behavior

UBL3 Interaction with α-Synuclein Is Downregulated by Silencing MGST3

Ubiquitin-like 3 (UBL3) is a membrane-anchored protein that plays a crucial role in sorting proteins into small extracellular vesicles. Aggregations of alpha-synuclein (α-syn) are associated with the pathology of neurodegenerative diseases such as Parkinson’s disease. Recently, the interaction between UBL3 and α-syn was discovered, with potential implications in clearing excess α-syn from neurons and its role in disease spread. However, the regulator that can mediate the interaction between UBL3 and α-syn remains unclear. In this study, using the split gaussian luciferase complementation assay and RNA interference technology, we identified that QSOX2, HTATIP2, UBE3C, MGST3, NSF, HECTD1, SAE1, and ATG3 were involved in downregulating the interaction between UBL3 and α-syn. Notably, silencing MGST3 had the most significant impact. Immunocytochemistry staining confirmed the impact of MGST3 silencing on the co-localization of UBL3 and α-syn in cells. MGST3 is a part of the antioxidant system, and silencing MGST3 is believed to contribute to oxidative stress. We induced oxidative stress with hydrogen peroxide, observing its effect on the UBL3-α-syn interaction, and showing that 800 µM of H2O2 downregulated this interaction. In conclusion, silencing MGST3 downregulates the interaction between UBL3 and α-syn

Distinct microglial response against Alzheimer’s amyloid and tau pathologies characterized by P2Y12 receptor

Microglia are the resident phagocytes of the central nervous system, and microglial activation is considered to play an important role in the pathogenesis of neurodegenerative diseases. Recent studies with single-cell RNA analysis of CNS cells in Alzheimer’s disease (AD) and diverse other neurodegenerative conditions revealed that the transition from homeostatic microglia to disease-associated microglia (DAM) was defined by changes of gene expression levels, including down-regulation of the P2Y12 receptor (P2Y12R). However, it is yet to be clarified in AD brains whether and when this down-regulation occurs in response to amyloid-β (Aβ) and tau depositions, which are core pathological processes in the disease etiology. To further evaluate the significance of P2Y12R alterations in the neurodegenerative pathway of AD and allied disorders, we generated an anti-P2Y12R antibody and examined P2Y12R expressions in the brains of humans and model mice bearing Aβ and tau pathologies. We observed that the brains of both AD and non-AD tauopathy patients and tauopathy model mice (rTg4510 and PS19 mouse lines) displayed declined microglial P2Y12R levels in regions enriched with tau inclusions, despite an increase in the total microglial population. Notably, diminution of microglial immunoreactivity with P2Y12R was noticeable prior to massive accumulations of phosphorylated tau aggregates and neurodegeneration in rTg4510 mouse brains, despite a progressive increase of total microglial population. On the other hand, Iba1-positive microglia encompassing compact and dense-cored Aplaques expressed P2Y12R at varying levels in amyloid precursor protein (APP) mouse models (APP23 and AppNL-F/NL-F mice). By contrast, neuritic plaques in AD brains were associated with P2Y12R-negative microglia. These data suggest that the down-regulation of microglia P2Y12R, which is characteristic of DAM, is intimately associated with tau rather than Aβ pathologies from an early stage and could be a sensitive index for neuroinflammatory responses to AD-related neurodegenerative processes