Gene-gene functional relationships in Alzheimer's disease: CELF1 regulates KLC1 alternative splicing.

The causes of Alzheimer's disease (AD) are poorly understood, although many genes are known to be involved in this pathology. To gain insights into the underlying molecular mechanisms, it is essential to identify the relationships between individual AD genes. Previous work has shown that the splice variant E of KLC1 (KLC1_vE) promotes AD, and that the CELF1 gene, which encodes an RNA-binding protein involved in splicing regulation, is at a risk locus for AD. Here, we identified a functional link between CELF1 and KLC1 in AD pathogenesis. Transcriptomic data from human samples from different ethnic groups revealed that CELF1 mRNA levels are low in AD brains, and the splicing pattern of KLC1 is strongly correlated with CELF1 expression levels. Specifically, KLC1_vE is negatively correlated with CELF1. Depletion and overexpression experiments in cultured cells demonstrated that the CELF1 protein down-regulates KLC1_vE. In a cross-linking and immunoprecipitation sequencing (CLIP-seq) database, CELF1 directly binds to KLC1 RNA, following which it likely modulates terminal exon usage, hence KLC1_vE formation. These findings reveal a new pathogenic pathway where a risk allele of CELF1 is associated with reduced CELF1 expression, which up-regulates KLC1_vE to promote AD.

Novel insights into presenilin 1 mutation associated with a distinctive dementia phenotype and cotton wool plaques.

BACKGROUND: The mutations in the presenilin 1 gene (PSEN1) are the main cause of familial Alzheimer's disease. PSEN1 mutations affect amyloid-beta peptide production, which accumulates in the brain as senile plaque and cotton wool plaques (CWPs) and relates to other neurodegenerative disorders. Here we report the second case of the PSEN1 G266S mutation, which showed distinctive neuropathological features, including abundant CWPs. Lewy body pathology, and altered amyloid-beta production. METHOD: Using the proband's samples, we performed genetic analysis of the PSEN1, APP, MAPT, and APOE genes, histopathological and immunohistochemical analysis of the brain tissue, and biochemical analysis of Aß production in COS cells transfected with wild-type or mutant PSEN1. RESULTS: The patient presented with memory loss, abnormal behavior, and visual hallucinations. Brain scans showed reduced blood flow, mild atrophy, and white matter lesions. Genetic analysis revealed a heterozygous mutation at codon 266 (G266S) of PSEN1 and polymorphism of MAPT (Q230R). The brain had many CWPs, severe cerebral amyloid angiopathy (CAA), senile plaque, Lewy bodies, and neurites. Electron microscopy displayed myelinated fiber degeneration, mitochondrial damage, and amyloid fibrils in the white matter. The production level of Aß42 in PSEN1 G266S-transfected cells significantly increased. CONCLUSION: Our findings suggest that the PSEN1 G266S mutation may cause a heterogeneous clinical and pathological phenotype, influenced by other genetic or environmental factors.

Japan-Multimodal Intervention Trial for the Prevention of Dementia: A randomized controlled trial.

INTRODUCTION: We examined the efficacy of a multidomain intervention in preventing cognitive decline among Japanese older adults with mild cognitive impairment (MCI). METHODS: Participants aged 65-85 years with MCI were randomized into intervention (management of vascular risk factors, exercise, nutritional counseling, and cognitive training) and control groups. The primary outcome was changes in the cognitive composite score over a period of 18 months. RESULTS: Of 531 participants, 406 completed the trial. The between-group difference in composite score changes was 0.047 (95% CI: -0.029 to 0.124). Secondary analyses indicated positive impacts of interventions on several secondary health outcomes. The interventions appeared to be particularly effective for individuals with high attendance during exercise sessions and those with the apolipoprotein E ε4 allele and elevated plasma glial fibrillary acidic protein levels. DISCUSSION: The multidomain intervention showed no efficacy in preventing cognitive decline. Further research on more efficient strategies and suitable target populations is required. HIGHLIGHTS: This trial evaluated the efficacy of multidomain intervention in individuals with MCI. The trial did not show a significant difference in preplanned cognitive outcomes. Interventions had positive effects on a wide range of secondary health outcomes. Those with adequate adherence or high risk of dementia benefited from interventions.

Effects of home-based bodyweight squat training on neuromuscular properties in community-dwelling older adults.

BACKGROUND: It is important to investigate neural as well as muscle morphological adaptations to evaluate the effects of exercise training on older adults. AIMS: This study was aimed to investigate the effects of home-based bodyweight squat training on neuromuscular adaptation in older adults. METHODS: Twenty-five community-dwelling older adults (77.7 ± 5.0 years) were assigned to squat (SQU) or control (CON) groups. Those in the SQU group performed 100 bodyweight squats every day and the others in the CON group only performed daily activities for 4 months. Maximum knee extension torque and high-density surface electromyography during submaximal contraction were assessed. Individual motor units (MUs) were identified and divided into relatively low or high-recruitment threshold MU groups. Firing rates of each MU group were calculated. The muscle thickness and echo intensity of the lateral thigh were assessed using ultrasound. As physical tests, usual gait speed, timed up and go test, grip strength, and five-time chair stand test were performed. RESULTS: While no improvements in muscle strength, muscle thickness, echo intensity, or physical tests were noted in either group, the firing rate of relatively low recruitment threshold MUs significantly decreased in the SQU group after intervention. CONCLUSIONS: These results suggest that low-intensity home-based squat training could not improve markedly muscle strength or physical functions even if high-repetition and high frequency exercise, but could modulate slightly neural activation in community-dwelling older adults.

Ultrastructural and biochemical classification of pathogenic tau, α-synuclein and TDP-43.

Intracellular accumulation of abnormal proteins with conformational changes is the defining neuropathological feature of neurodegenerative diseases. The pathogenic proteins that accumulate in patients' brains adopt an amyloid-like fibrous structure and exhibit various ultrastructural features. The biochemical analysis of pathogenic proteins in sarkosyl-insoluble fractions extracted from patients' brains also shows disease-specific features. Intriguingly, these ultrastructural and biochemical features are common within the same disease group. These differences among the pathogenic proteins extracted from patients' brains have important implications for definitive diagnosis of the disease, and also suggest the existence of pathogenic protein strains that contribute to the heterogeneity of pathogenesis in neurodegenerative diseases. Recent experimental evidence has shown that prion-like propagation of these pathogenic proteins from host cells to recipient cells underlies the onset and progression of neurodegenerative diseases. The reproduction of the pathological features that characterize each disease in cellular and animal models of prion-like propagation also implies that the structural differences in the pathogenic proteins are inherited in a prion-like manner. In this review, we summarize the ultrastructural and biochemical features of pathogenic proteins extracted from the brains of patients with neurodegenerative diseases that accumulate abnormal forms of tau, α-synuclein, and TDP-43, and we discuss how these disease-specific properties are maintained in the brain, based on recent experimental insights.

Possible correlated variation of GABAA receptor α3 expression with hippocampal cholinergic neurostimulating peptide precursor protein in the hippocampus.

Cholinergic neural activation from the medial septal nucleus to hippocampus plays a crucial role in episodic memory as a regulating system for glutamatergic neural activation in the hippocampus. As a candidate regulating factor for acetylcholine synthesis in the medial septal nucleus, hippocampal cholinergic neurostimulating peptide (HCNP) was purified from the soluble fraction of young adult rat hippocampus. HCNP is released from its precursor protein (HCNP-pp), also referred to as phosphatidylethanolamine-binding protein 1. We recently reported that HCNP-pp conditional knockout (KO) mice, in which the HCNP-pp gene was knocked out at 3 months of age by tamoxifen injection, display no significant behavioral abnormalities, whereas HCNP-pp KO mice have a diminished cholinergic projection to CA1 and a decreased of theta activity in CA1. In this study, to address whether HCNP-pp reduction in early life is associated with behavioral changes, we evaluated the behavior of HCNP-pp KO mice in which HCNP-pp was downregulated from an early phase (postnatal days 14-28). As unexpected, HCNP-pp KO mice had no behavioral deficits. However, a significant positive correlation between HCNP-pp and gamma-aminobutyric acid A (GABAA) receptor α3 subunit mRNA expression was found in individuals. This finding suggests involvement of HCNP-pp in regulating GABAA receptor α3 gene expression.

Favipiravir for the treatment of patients with COVID-19: a systematic review and meta-analysis.

BACKGROUND: Favipiravir possesses high utility for treating patients with COVID-19. However, research examining the efficacy and safety of favipiravir for patients with COVID-19 is limited. METHODS: We conducted a systematic review of published studies reporting the efficacy of favipiravir against COVID-19. Two investigators independently searched PubMed, the Cochrane Database of Systematic Reviews, MedRxiv, and ClinicalTrials.gov (inception to September 2020) to identify eligible studies. A meta-analysis was performed to measure viral clearance and clinical improvement as the primary outcomes. RESULTS: Among 11 eligible studies, 5 included a comparator group. Comparing to the comparator group, the favipiravir group exhibited significantly better viral clearance on day 7 after the initiation of treatment (odds ratio [OR] = 2.49, 95% confidence interval [CI] = 1.19-5.22), whereas no difference was noted on day 14 (OR = 2.19, 95% CI = 0.69-6.95). Although clinical improvement was significantly better in the favipiravir group on both days 7 and 14, the improvement was better on day 14 (OR = 3.03, 95% CI = 1.17-7.80) than on day 7 (OR = 1.60, 95% CI = 1.03-2.49). The estimated proportions of patients with viral clearance in the favipiravir arm on days 7 and 14 were 65.42 and 88.9%, respectively, versus 43.42 and 78.79%, respectively, in the comparator group. The estimated proportions of patients with clinical improvement on days 7 and 14 in the favipiravir group were 54.33 and 84.63%, respectively, compared with 34.40 and 65.77%, respectively, in the comparator group. CONCLUSIONS: Favipiravir induces viral clearance by 7 days and contributes to clinical improvement within 14 days. The results indicated that favipiravir has strong possibility for treating COVID-19, especially in patients with mild-to-moderate illness. Additional well-designed studies, including examinations of the dose and duration of treatment, are crucial for reaching definitive conclusions.

Evidence for Altered Phosphoinositide Signaling-Associated Molecules in the Postmortem Prefrontal Cortex of Patients with Schizophrenia.

Phosphoinositides (PIs) play important roles in the structure and function of the brain. Associations between PIs and the pathophysiology of schizophrenia have been studied. However, the significance of the PI metabolic pathway in the pathology of schizophrenia is unknown. We examined the expression of PI signaling-associated proteins in the postmortem brain of schizophrenia patients. Protein expression levels of phosphatidylinositol 4-phosphate 5-kinase type-1 gamma (PIP5K1C), phosphatidylinositol 4-kinase alpha (PIK4CA, also known as PIK4A), phosphatase and tensin homolog deleted from chromosome 10 (PTEN), protein kinase B (Akt), and glycogen synthase kinase 3ß (GSK3ß) were measured using enzyme-linked immunosorbent assays and multiplex fluorescent bead-based immunoassays of the prefrontal cortex (PFC) of postmortem samples from 23 schizophrenia patients and 47 normal controls. We also examined the association between PIK4CA expression and its genetic variants in the same brain samples. PIK4CA expression was lower, whereas Akt expression was higher, in the PFC of schizophrenia patients than in that of controls; PIP5K1C, PTEN, and GSK3ß expression was not different. No single-nucleotide polymorphism significantly affected protein expression. We identified molecules involved in the pathology of schizophrenia via this lipid metabolic pathway. These results suggest that PIK4CA is involved in the mechanism underlying the pathogenesis of schizophrenia and is a potential novel therapeutic target.

Deficiency of a sulfotransferase for sialic acid-modified glycans mitigates Alzheimer's pathology.

We previously showed that microglial keratan sulfate (KS) was induced in amyotrophic lateral sclerosis. However, the functional roles of the glycan and its synthetic enzyme in neurodegenerative diseases, such as Alzheimer's disease (AD), a progressive disorder, are unclear. In our study, KS modified with sialic acids having a molecular mass of 125-220 kDa and the carbohydrate sulfotransferase GlcNAc6ST1 were up-regulated in the brains of two transgenic mouse models (J20 and Tg2576) and the brains of patients with AD. GlcNAc6ST1-deficient J20 (J20/GlcNAc6ST1-/-) mice demonstrated a complete absence of the microglial sialylated KS. J20/GlcNAc6ST1-/- primary microglia showed an increased level of amyloid-ß phagocytosis and were hyperresponsive to interleukin 4, a potent antiinflammatory cytokine. Moreover, J20/GlcNAc6ST1-/- mice manifested reduced cerebral amyloid-ß deposition. GlcNAc6ST1-synthesizing sialylated KS thus modulates AD pathology. Inhibition of KS synthesis by targeting GlcNAc6ST1 may therefore be beneficial for controlling AD pathogenesis.

Comprehensive quantification of purine and pyrimidine metabolism in Alzheimer's disease postmortem cerebrospinal fluid by LC-MS/MS with metal-free column.

The metabolome presence of nucleobases, nucleosides, nucleotides and related phosphorylated metabolites has been examined for Alzheimer's disease (AD). Although reversed-phase liquid chromatography tandem mass spectrometry (LC-MS/MS) has been used for the determination of these analytes, they were limited in chromatographic signal intensity and reproducibility owing to significant peak tailing caused by complexing with metallic cations and phosphate groups. In this work, we applied LC-MS/MS analysis with a metal-free column for comprehensive quantification of 40 analytes regarding to purine and pyrimidine metabolism in postmortem cerebrospinal fluid (pCSF) from AD patients. For the analytical column, an InertSustain AQ-C18 metal-free PEEK column was used. MS detection was by electrospray positive ionization. The metal-free column allowed for sharp peak detection of highly polar metabolites within a running time of 17 min. In validation, the limits of detection (LOD), the limit of quantitation (LOQ) and recovery value using a pooled pCSF sample are 1-500 nM, 0.5-250 nM and a range of 53.1-144.0% (RSD ranged from 0.4 to 19.6%). The developed LC-MS/MS method utilizing a metal-free column provides an accurate quantification of some metabolites regarding purine and pyrimidine metabolism in pCSF samples obtained from AD patients.

Isotope Corrected Chiral and Achiral Nontargeted Metabolomics: An Approach for High Accuracy and Precision Metabolomics Based on Derivatization and Its Application to Cerebrospinal Fluid of Patients with Alzheimer's Disease.

We propose a chiral metabolomics approach based on a data-dependent MS/MS analysis (DDA) using high-resolution quadrupole-time-of-flight mass spectrometry (Q-TOFMS) and 13C-isotope coded derivatization (ICD) reagents, i.e., iDMT-( S)-A and iDMT-( S)-PO. The advantage of the method is the correction of all detected derivatives by parallel derivatization of the isotope-coded and noncoded reagents. The automatic data analysis platform using an MSDIAL and ICD discrimination program, called DINA, was also developed and used for the data analysis process. As a result, a 0.5-2.0% (d-/l-isomer) variation of the isomers was correctly recognized in the automatic data analysis step. Both the semiquantitative comparison and identification efficiency were improved as a result of the high resolution/accuracy of the MS and MS/MS spectra derived from the DDA analysis. This method was used for biomarker discovery in the cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD). Twenty-four biomarker candidates were successfully determined, including 8 chiral ones.

Factors influencing hospital admission among patients with autopsy-confirmed dementia.

BACKGROUND: The symptoms of geriatric syndromes and the behavioural and psychological symptoms of dementia (BPSD), in addition to clinical conditions, are associated with hospital admission among dementia patients. However, the principal factors that necessitate hospital admission among dementia patients have not been fully elucidated. METHODS: We retrospectively reviewed the data in the medical and autopsy reports of patients who had been treated at a hospital in Toyohashi, Japan. Each patient had been hospitalized sometime between 2012 and 2016 and underwent a brain autopsy. Dementia and the subtypes of dementia were diagnosed neuropathologically. Information about patients' general backgrounds, clinical conditions at the time of admission, and the geriatric syndrome symptoms and BPSD before admission was collected; comparisons were then made between patients with and without dementia and among those with the different major subtypes of dementia. Then, the factors relating to hospital admission of dementia patients were comprehensively evaluated by using principle component analysis. RESULTS: Of the 128 eligible patients, 100 (78.1%) had dementia. In the comparison of patients with and without dementia, patients without dementia were younger at both admission (P = 0.034) and death (P = 0.003). Among the patients with dementia with Lewy bodies, delusions had a significantly high prevalence (P = 0.014). Principal component analysis identified nine components (disinhibition, irritability/lability, agitation/aggression, anxiety, delusions, sleep/night-time behaviour disorders, hallucinations, aberrant motor behaviour, and speech impairment) as the principal factors related to hospital admission among dementia patients. Thus, BPSD were identified as principal factors. CONCLUSIONS: Compared to other factors, BPSD are more likely to cause dementia patients to be admitted to hospital. The present results indicate that measures should be taken to ameliorate the difficulties associated with caring for patients with BPSD at home.

[Effects of drug treatment on the surviral-time in patients with dementia].

AIM: The effect of polypharmacy on the surviral-time in patients with dementia has never been fully elucidated. METHODS: A retrospective study was conducted in a hospital in Aichi, Japan, by reviewing the medical charts and autopsy reports. Patients were hospitalized and neuropathologically diagnosed with dementia. The data on medication was collected from the prescribed drugs taking right before the admission. Patients were divided into two groups according to the number of prescribed drugs: ≥ 5 drugs (polypharmacy) vs. ≤ 4 drugs (non-polypharmacy). "Drugs to be prescribed with special caution" were defined in accordance with the guidelines for medical treatment and its safety in the elderly (2015). RESULTS: Seventy-six patients were eligible, and 39.5% of patients had polypharmacy. The Kaplan-Meier method showed that the polypharmacy group tended to have a shorter survival-time than the non-polypharmacy group (p=0.067). A Cox proportional hazard model showed that the polypharmacy group tended to have a higher risk for a reduced survival-time than the non-polypharmacy group, and this tendency was more prominent after adjusting for sex and age at admission (adjusted hazard ratio, 1.631; 95% confidence interval, 0.991-2.683; p=0.054). "Drugs to be prescribed with special caution", including hypnotic-sedative drugs, antianxiety drugs, antipsychotics, and benzodiazepines, were not found to be risk factors for a reduced survival-time. CONCLUSIONS: The present study showed that polypharmacy in terminal patients with dementia tended to carry a risk for reducing their remaining lifespan. The results warrant further additional study.

Integrated analysis of human genetic association study and mouse transcriptome suggests LBH and SHF genes as novel susceptible genes for amyloid-ß accumulation in Alzheimer's disease.

Alzheimer's disease (AD) is a common neurological disease that causes dementia in humans. Although the reports of associated pathological genes have been increasing, the molecular mechanism leading to the accumulation of amyloid-ß (Aß) in human brain is still not well understood. To identify novel genes that cause accumulation of Aß in AD patients, we conducted an integrative analysis by combining a human genetic association study and transcriptome analysis in mouse brain. First, we examined genome-wide gene expression levels in the hippocampus, comparing them to amyloid Aß level in mice with mixed genetic backgrounds. Next, based on a GWAS statistics obtained by a previous study with human AD subjects, we obtained gene-based statistics from the SNP-based statistics. We combined p values from the two types of analysis across orthologous gene pairs in human and mouse into one p value for each gene to evaluate AD susceptibility. As a result, we found five genes with significant p values in this integrated analysis among the 373 genes analyzed. We also examined the gene expression level of these five genes in the hippocampus of independent human AD cases and control subjects. Two genes, LBH and SHF, showed lower expression levels in AD cases than control subjects. This is consistent with the gene expression levels of both the genes in mouse which were negatively correlated with Aß accumulation. These results, obtained from the integrative approach, suggest that LBH and SHF are associated with the AD pathogenesis.

[The consciousness survey and the effect of educational intervention of Advance Care Planning (ACP) including post-mortem to elderly residents living in old New Town of big city].

AIM: Awareness reform aims to enable survival in an aging society, and ultimately, improve healthcare. An ideal way to achieve this is by implementing Advance directive (Ad) and Advance Care Planning (ACP), which do not usually include postmortem events. This study aims to create opportunities for Ad and ACP to include the postmortem period as a trigger for this awareness reform. METHODS: We conducted an Ad/ACP enlightenment lecture, and a questionnaire survey pre- and post-lecture for the elderly in old New Town, which is known for its aging society. The questionnaire comprised 38 multiple-choice questions covering 6 themes assuming an advanced state of dementia. RESULTS: There were 35 participants (7 men and 22 women) aged 40-89 years. Several people left during the lecture, making it difficult to capture the precise transformation effect with regard to changing of mind. However, the effect of enlightenment was identified as a result of the consciousness survey. A statistically significant change in consciousness occurred in response to social contribution after death. Furthermore, notably more people wanted emergency transportation compared to those wanting resuscitation and extension of life. CONCLUSIONS: The medical treatment desired might vary over time. Even the desire for life extension may differ significantly among individuals. This survey indicated a divergent view between the general public and medical staff, regarding a series of medical actions. We must persistently promote opportunities for enlightenment in cooperation with the general public (i.e., the communities and families we serve).

Lysophosphatidylcholine export by human ABCA7.

The ATP-binding cassette transporter A7 (ABCA7), which is highly expressed in the brain, is associated with the pathogenesis of Alzheimer's disease (AD). However, the physiological function of ABCA7 and its transport substrates remain unclear. Immunohistochemical analyses of human brain sections from AD and non-AD subjects revealed that ABCA7 is expressed in neuron and microglia cells in the cerebral cortex. The transport substrates and acceptors were identified in BHK/ABCA7 cells and compared with those of ABCA1. Like ABCA1, ABCA7 exported choline phospholipids in the presence of apoA-I and apoE; however, unlike ABCA1, cholesterol efflux was marginal. Lipid efflux by ABCA7 was saturated by 5µg/ml apoA-I and was not dependent on apoE isoforms, whereas efflux by ABCA1 was dependent on apoA-I up to 20µg/ml and apoE isoforms. Liquid chromatography-tandem mass spectrometry analyses revealed that the two proteins had different preferences for phospholipid export: ABCA7 preferred phosphatidylcholine (PC)≥lysoPC>sphingomyelin (SM)=phosphatidylethanolamine (PE), whereas ABCA1 preferred PC>>SM>PE=lysoPC. The major difference in the pattern of lipid peaks between ABCA7 and ABCA1 was the high lysoPC/PC ratio of ABCA7. These results suggest that lysoPC is one of the major transport substrates for ABCA7 and that lysoPC export may be a physiologically important function of ABCA7 in the brain.

Immunohistochemical detection of the delayed formation of nonfibrillar large amyloid-ß aggregates.

The occurrence of senile plaques consisting of amyloid-ß protein (Aß) is a major neuropathological hallmark of Alzheimer's disease (AD). We previously developed and characterized monoclonal antibodies 31-2 and 75-2 that specifically bind to nonfibrillar Aß1-42 aggregates with diameters of more than 220 and 50 nm, respectively. Here, we report the use of these antibodies to examine the aggregation of exogenous Aß1-42 in cultured rat hippocampal neurons. From 6 to 24 h after transfection of Aß1-42, antibody 75-2 immunolabeled almost all transfected neurons, whereas 31-2-positive cells were restricted to a part of the transfected neurons and gradually increased in number. Expression of the F19S/L34P-mutant Aß1-42, which showed less of a tendency to aggregate, resulted in clearly reduced immunoreactivity to both antibodies. We also immunohistochemically investigated the temporal cortices of patients with AD and found that 31-2 preferentially labeled the cores of a subpopulation of large amyloid plaques. The relative number of 31-2-immunoreactive plaques was found to correlate with the Braak stages of neurofibrillary tangles, but not with that of amyloid plaques. These results suggest that 31-2-reactive Aß aggregates develop with a delayed time course in cultured neurons and amyloid plaques of AD brains.

Complement Activation in Capillary Cerebral Amyloid Angiopathy.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is classified as type 1 with capillary amyloid ß (Aß) or type 2 without capillary Aß. While it is known that CAA activates complement, an inflammatory mediator, there is no information on the relationship between capillary Aß and complement activation. METHODS: We evaluated 34 autopsy brains, including 22 with CAA and 12 with other neurodegenerative diseases. We assessed the vascular density of CAA by analyzing the expression of complement (C1q, C3d, C6, C5b-9), macrophage scavenger receptor (MSR), and apolipoprotein E (ApoE). RESULTS: Capillary immunostaining for C1q, C3d, MSR, and ApoE was identified almost exclusively in CAA-type1 brains. There was intense expression of C1q, C3d, MSR, and ApoE, as well as weaker expression of C5b-9 and C6 in the arteries/ arterioles of both CAA subtypes, but not in control brains. C5b-9 and C6 were preferentially expressed in arteries/arterioles with subcortical hemorrhage or cortical superficial siderosis. Triple immunofluorescence revealed that C1q, C3d, and ApoE were colocalized with Aß in CAA brain capillaries. CONCLUSION: Complement, MSR, and ApoE were only coexpressed in the presence of Aß accumulation in capillaries, suggesting a role for complement activation in the propagation of Aß. Additionally, C5b-9 expression may be associated with hemorrhagic brain injury in CAA.