Plaque Distribution Research Articles

Novel App knock-in mouse model shows key features of amyloid pathology and reveals profound metabolic dysregulation of microglia

BackgroundGenetic mutations underlying familial Alzheimer’s disease (AD) were identified decades ago, but the field is still in search of transformative therapies for patients. While mouse models based on overexpression of mutated transgenes have yielded key insights in mechanisms of disease, those models are subject to artifacts, including random genetic integration of the transgene, ectopic expression and non-physiological protein levels. The genetic engineering of novel mouse models using knock-in approaches addresses some of those limitations. With mounting evidence of the role played by microglia in AD, high-dimensional approaches to phenotype microglia in those models are critical to refine our understanding of the immune response in the brain.MethodsWe engineered a novel App knock-in mouse model (AppSAA) using homologous recombination to introduce three disease-causing coding mutations (Swedish, Arctic and Austrian) to the mouse App gene. Amyloid-β pathology, neurodegeneration, glial responses, brain metabolism and behavioral phenotypes were characterized in heterozygous and homozygous AppSAA mice at different ages in brain and/ or biofluids. Wild type littermate mice were used as experimental controls. We used in situ imaging technologies to define the whole-brain distribution of amyloid plaques and compare it to other AD mouse models and human brain pathology. To further explore the microglial response to AD relevant pathology, we isolated microglia with fibrillar Aβ content from the brain and performed transcriptomics and metabolomics analyses and in vivo brain imaging to measure energy metabolism and microglial response. Finally, we also characterized the mice in various behavioral assays.ResultsLeveraging multi-omics approaches, we discovered profound alteration of diverse lipids and metabolites as well as an exacerbated disease-associated transcriptomic response in microglia with high intracellular Aβ content. The AppSAA knock-in mouse model recapitulates key pathological features of AD such as a progressive accumulation of parenchymal amyloid plaques and vascular amyloid deposits, altered astroglial and microglial responses and elevation of CSF markers of neurodegeneration. Those observations were associated with increased TSPO and FDG-PET brain signals and a hyperactivity phenotype as the animals aged.DiscussionOur findings demonstrate that fibrillar Aβ in microglia is associated with lipid dyshomeostasis consistent with lysosomal dysfunction and foam cell phenotypes as well as profound immuno-metabolic perturbations, opening new avenues to further investigate metabolic pathways at play in microglia responding to AD-relevant pathogenesis. The in-depth characterization of pathological hallmarks of AD in this novel and open-access mouse model should serve as a resource for the scientific community to investigate disease-relevant biology.

The characteristics of intracranial plaques of unilateral, anterior circulation embolic stroke of undetermined source: An analysis of different subtypes based on high-resolution imaging.

The aim was to investigate the characteristics of non-stenotic intracranial plaque (NSIP) in embolic stroke of undetermined source (ESUS) subtypes by high-resolution magnetic resonance imaging. Consecutive patients with ESUS who were mandatory for high-resolution magnetic resonance imaging were retrospectively enrolled. Based on the location and arterial supply of the infarct, the ESUS were categorized into three types: cortical ESUS, subcortical ESUS and mixed ESUS. The NSIP parameters including plaque location, morphology (plaque distribution, remodeling index and plaque burden) and composition (thick fibrous cap, discontinuity of plaque surface, intraplaque hemorrhage and complicated plaque) were evaluated amongst the subtypes. Of 243 patients, there were 87 (35.8%) cortical ESUS, 127 (52.3%) subcortical ESUS and 29 (11.9%) mixed ESUS. Significant differences were found in plaque location (p < 0.001), plaque quadrant (p < 0.001), remodeling index (p < 0.001), plaque burden (p < 0.001), discontinuity of plaque surface (p < 0.001), intraplaque hemorrhage (p=0.001) and complicated plaque (p < 0.001) of ipsilateral NISP amongst the different ESUS subtypes, except for fibrous cap (p=0.135). However, no differences were found amongst contralateral NISP. In addition, the clinical characteristics of the differences between ESUS subtypes were striking, including age (p=0.004), initial National Institutes of Health Stroke Scale (p < 0.001), coronary artery disease (p=0.039), serum urea (p=0.011) and creatinine (p=0.002). This is the first report of significantly heterogeneous characteristics of ipsilateral NSIP and clinical findings amongst ESUS subtypes, which may suggest their different underlying mechanisms.

Dental plaque and gingival bleeding in adolescents with juvenile idiopathic arthritis and controls: a multilevel analysis

Objective To explore whether plaque and gingival bleeding are more frequently experienced by adolescents with juvenile idiopathic arthritis (JIA) compared to matched controls without JIA; explore whether surface- and site-specific periodontal outcomes vary between the two groups; and for participants with JIA, investigate associations between disease-specific features and periodontal outcomes. Material and methods In this comparative cross-sectional study, selected surfaces, and sites of index teeth in 10–16-year-olds with JIA and matched controls were examined by modified versions of Simplified Oral Hygiene Index (OHI-S) and Gingival Bleeding Index (GBI). Mixed-effects logistic regressions, reporting odds ratios (OR) with 95% confidence interval (CI), were applied. Intra-class correlation coefficients (ICCs) were calculated to quantify the degree of dependency of measures within the same individual. Results 144 and 159 adolescents with JIA were evaluated according to OHI-S and GBI; corresponding numbers of controls were 154 and 161. Plaque and gingival bleeding were more frequent in individuals with JIA than controls. Adjusted analyses showed association between JIA status and OHI-S > 0 (OR = 2.33, 95% CI: 1.47 − 3.67, ICC = 0.45) and GBI > 0 (OR = 1.54, 95% CI: 1.10 − 2.16, ICC = 0.41 and 0.30). Surface-specific distribution of plaque varied among the two groups. Conclusions Our results highlight the importance of increased awareness of oral health care in patients with JIA and that surface- and site-specific differences in periodontal outcomes exist between individuals with JIA and controls. Few JIA disease-specific variables associated with plaque or gingival bleeding.

HR-MRI findings of intracranial artery stenosis and distribution of atherosclerotic plaques caused by different etiologies.

To investigate the etiology of intracranial artery stenosis and the distribution characteristics of intracranial artery atherosclerotic stenosis using high-resolution magnetic resonance imaging (HR-MRI). A total of 262 patients with intracranial artery stenosis that underwent HR-MRI from November 2019 to December 2020 were retrospectively enrolled. The etiology of intracranial anterior and posterior circulation artery stenosis was analyzed, and the relationship between the location of plaques and the distribution characteristics of plaques and the occurrence of ischemic stroke was summarized. A total of 276 plaques were identified with HR-MRI. There were 101 cases (36.59%) in the middle cerebral artery (MCA), 14 cases (5.07%) in the posterior cerebral artery (PCA), 90 cases (32.62%) in vertebral artery (VA), and 71 cases (25.72%) in the basilar artery (BA). The infarct rate of ventral and superior wall MCA plaques was higher than that of dorsal and inferior wall (63.33% vs 31.25% P = 0.021) (100.00% vs 50% P = 0.022). MCA with plaques throughout the course had the greatest degree of stenosis (P < 0.001). Sphenoid segment (M1) of MCA was most susceptible (85 cases, 84.16%), MCA plaques were most common in the proximal M1 segment (35 cases, 34.65%), and most BA plaques were found in the distal segment (28 cases, 39.44%). PCA plaques were most frequently involved in traffic anterior segment (P1) (7 cases, 50.00%). HR-MRI could provide accurate imaging reference for clinical evaluation of intracranial arterial stenosis and formulation of treatment plans. The intracranial arterial plates mostly appeared in the middle cerebral artery and vertebral artery. Middle cerebral arteries with atherosclerotic plaques are more likely to narrow.

Rational Design of Quinoxalinone-Based Red-Emitting Probes for High-Affinity and Long-Term Visualizing Amyloid-β In Vivo.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with insidious onset, and the deposition of amyloid-β (Aβ) is believed to be one of the main cause. Fluorescence imaging is a promising technique for this task, but the Aβ gold standard probe ThT developed based on this still has shortcomings. The development of a new fluorescent probe to detect Aβ plaques is thought to be essential. Herein, a series of red to near-infrared emitting fluorescent probes QNO-ADs with newly quinoxalinone skeleton are designed to detect Aβ plaques. They all demonstrate excellent optical properties and high binding affinity (∼Kd = 20 nM) to Aβ aggregates. As the most outstanding candidate, QNO-AD-3 shows significant signal-to-noise (S/N) ratio at the level of in vitro binding studies, and the brilliant fluorescence staining results in favor of grasping the approximate distribution of Aβ plaques in the brain slice. In vivo Aβ plaques imaging suggests that QNO-AD-3 can cross the BBB and have a long retention time in the brain with low biological toxicity. In addition, the results of docking theoretical calculation also provide some references for the design of Aβ probe. Overall, given the high affinity of QNO-AD-3 and the ability to monitor Aβ plaques for a long time that is not common now, we believe QNO-AD-3 will be an effective tool for an Aβ-related matrix and AD disease research in the future.

AIE-based fluorescent micro-optical sectioning tomography for automatic 3D mapping of β-amyloid plaques in Tg mouse whole brain

Rapid verification and three-dimensional (3D) mapping of β-amyloid (Aβ) plaques in mouse whole brain is of great significance in early diagnosis of Alzheimer’s disease (AD) due to the intricate relationship of Aβ plaques with their surrounding microenvironment. Previously reported fluorescent labelling to locate Aβ plaques usually require lengthy permeation/staining/washing procedures to eliminate non-specific binding and improve fluorescence signal-to-noise ratio, which is inaccessible to automatic brain wide 3D imaging. Here we report a kind of water-soluble fluorescent probes with aggregation-induced emission (AIE) activities, named AIEgens, which can rapidly permeate and stain Aβ plaques of transgenic (Tg) mouse brain sections into 8 μm of depth within 1 min. The excellent water-solubility, specificity and sensitivity of AIEgens for Aβ plaques enable rapid staining and washing-free imaging of brain sections. The automatic 3D mapping of Aβ plaques in Tg mouse’s whole brain is implemented through the cycling process of in situ real-time mechanical sectioning, staining and imaging with AIEgens in fluorescent micro-optical sectioning tomography (fMOST) system. The AIE-based fMOST, which integrates the in-situ staining/imaging/sectioning steps of Tg mouse’s whole brain, provides an automatic 3D mapping solution to access the size, morphology and 3D distribution of Aβ plaques in mouse whole brain, which would help to explore the correlation between Aβ structure and neurodegenerative activity.

Lipid-lowering treatment in a rabbit model of atherosclerosis: a vessel wall magnetic resonance imaging study.

BackgroundVessel wall magnetic resonance imaging (VWMRI) is currently one of the best imaging techniques for the non-invasive evaluation of intracranial atherosclerotic lesions. However, it is still impossible to obtain pathological specimens of intracranial atherosclerotic plaques in vivo. The establishment of experimental animal models of atherosclerotic lesions similar to those of humans could solve this deficiency.MethodsA model of abdominal aortic atherosclerosis in New Zealand white rabbits was established using abdominal aortic balloon dilatation combined with high-fat fodder. The pathological results were used as the reference standard for the successful establishment of the animal model. The rabbits with abdominal aortic atherosclerosis were randomly divided into the lipid-lowering treatment and the normal-fodder control groups. VWMRI and blood biochemical examinations were performed at 4, 12, and 24 weeks, and the radiologic-pathologic correlations were established.ResultsA rabbit abdominal aortic atherosclerosis model was established using balloon dilatation followed by high-fat fodder for 8 weeks. The lipid-lowering treatment reduced the plaque lipid core volume and decreased the plaque burden. However, it did not change plaque distribution, shape, or reverse vascular remodeling. Our pathological findings suggest that the lipid-lowering treatment reduced intraplaque macrophages but did not alter microvascular density.ConclusionsVWMRI accurately assessed the morphological changes of the plaques before and after the lipid-lowering treatment, and the results support the pathology results. VWMRI could be useful in experimental studies on the pathogenesis, diagnosis, and treatment of atherosclerotic lesions.

Influence of myocardial bridge on atherosclerotic plaque distribution and characteristics evaluated by near-infrared spectroscopy intravascular ultrasound

This study aims to clarify whether myocardial bridge (MB) could influence atherosclerotic plaque characteristics assessed using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) imaging. One hundred and sixteen patients who underwent percutaneous coronary intervention (PCI) using NIRS-IVUS imaging were included. MB was defined as an echo-lucent band surrounding left anterior descending artery (LAD). In MB patients, LAD was divided into three segments: proximal, MB, and distal segments. In non-MB patients, corresponding three segments were defined based on the average length of the above segments. Segmental maximum plaque burden and lipid content derived from NIRS-IVUS imaging in the section of maximum plaque burden were evaluated in each segment. Lipid content of atherosclerotic plaque was evaluated as lipid core burden index (LCBI) and maxLCBI4mm. LCBI is the fraction of pixels indicating lipid within a region multiplied by 1000, and the maximum LCBI in any 4-mm region was defined as maxLCBI4mm. MB was identified in 42 patients. MB was not associated with maximum plaque burden in proximal segment. LCBI and maxLCBI4mm were significantly lower in patients with MB than those without in proximal segment. Multivariable analysis demonstrated both MB and maximum plaque burden in proximal segment to be independent predictors of LCBI in proximal segment. Lipid content of atherosclerotic plaque assessed by NIRS-IVUS imaging was significantly smaller in patients with MB than those without. MB could be considered as a predictor of lipid content of atherosclerotic plaque when assessed by NIRS-IVUS imaging.

Atheromatosis of the brain-supplying arteries: Circle of Willis, basilar, vertebral and their branches

PurposeAtherosclerotic plaques in the brain-supplying arteries are slowly-developing alterations of vascular structures that can lead to neurological impairment due to stenosis and insufficient oxygenation of eloquent brain areas. The aim of this study is to provide detailed demographic information related to the incidence of atherosclerotic plaques in the cerebral arteries. Material and methodsForty-eight circles of Willis (21 men, 21 women, mean age: 70.26, six samples unknown) were macroscopically analyzed for length, diameter, and presence of atherosclerotic plaques. Statistical analysis was used to identify potential differences in the locations and frequencies of atherosclerotic plaques in relation to age and sex. ResultsThe study sample revealed 261 atherosclerotic plaques. The key findings were significant correlations between plaque development and age and between plaque location and age; however, there was no significant sex difference. ConclusionThe upper and lower branches of the middle cerebral artery (MCA) were novel locations predisposing to plaque development. A cut-off value at 60 years revealed a significant difference in plaque development and distribution. There were no significant sex differences in the occurrence of atherosclerotic plaques.

APOE \u03b54, Alzheimer\u2019s disease neuropathology and sleep disturbance, in individuals with and without dementia

BackgroundApolipoprotein E epsilon 4 (APOE-ε4) carrier status is an established risk factor for Alzheimer’s disease (AD) dementia. It has also been linked with sleep disturbance in healthy older adults and increased insomnia risk. This association may be driven by the effect of APOE-ε4 on AD pathological change, itself associated with sleep abnormalities. To assess this relationship, we have evaluated post-mortem neuropathological findings in patients with and without cognitive impairment and AD pathology, who had extensive clinical assessment within 12 months of death.MethodsThis retrospective cohort study used UK Brain Banks Network data. Eligible subjects were aged over 50, with pre-mortem neuropsychiatry inventory scores of sleep disturbance (NPI-K), neurocognitive testing and functional cognitive status assessment (Clinical Dementia Rating scale). Neuropathological data included Thal phase, Braak stage and CERAD scores (measures of Aβ plaque distribution, tangle distribution and neuritic plaque density, respectively) combined to form the National Institute on Aging Alzheimer’s Association (NIA-AA) ABC score reflecting AD neuropathology. Participants with other significant intracerebral pathology or pathological features of non-AD dementia were excluded.Multivariate linear regression was performed with NPIK Global Score (NPIK frequency score multiplied by severity score) as the dependent variable and APOE-ε4 heterozygosity or homozygosity as independent variables. Covariates included age, gender, APOE-ε2 status and ABC NPI measures reflecting depression and anxiety. Further models stratified by ABC score and functional cognitive status were also produced.ResultsSeven hundred twenty-eight records were identified. Two hundred two participants were included in the final analysis: mean (SD) age 84.0 (9.2) and MMSE 14.0 (11.8). Mean sleep disturbance scores were highest in ε4 homozygosity (n=11), 4.55 (5.4); intermediate in ε4 heterozygosity (n=95), 2.03 (4.0); and lowest in non-ε4 carriers (n=96), 1.36 (3.3). Within the full sample, controlling for pathological status, age, gender, depression, anxiety and CDR-SOB status, APOE-ε4 homozygosity was associated with sleep disturbance (β 2.53, p=0.034). APOE-ε4 heterozygosity was similarly associated in individuals without dementia (β 1.21, p=0.048).ConclusionThese findings lend weight to the hypothesis that APOE-ε4 affects sleep by mechanisms independent of AD pathological change. Evaluation of those mechanisms would enhance understanding of sleep disturbance pathways and potentially provide treatment targets.

Lesions without symptoms: understanding resilience to Alzheimer disease neuropathological changes.

Since the original description of amyloid-β plaques and tau tangles more than 100years ago, these lesions have been considered the neuropathological hallmarks of Alzheimer disease (AD). The prevalence of plaques, tangles and dementia increases with age, and the lesions are considered to be causally related to the cognitive symptoms of AD. Current schemes for assessing AD lesion burden examine the distribution, abundance and characteristics of plaques and tangles at post mortem, yielding an estimate of the likelihood of cognitive impairment. Although this approach is highly predictive for most individuals, in some instances, a striking mismatch between lesions and symptoms can be observed. A small subset of individuals harbour a high burden of plaques and tangles at autopsy, which would be expected to have had devastating clinical consequences, but remain at their cognitive baseline, indicating 'resilience'. The study of these brains might provide the key to understanding the 'black box' between the accumulation of plaques and tangles and cognitive impairment, and show the way towards disease-modifying treatments for AD. In this Review, we begin by considering the heterogeneity of clinical manifestations associated with the presence of plaques and tangles, and then focus on insights derived from the rare yet informative individuals who display high amounts of amyloid and tau deposition in their brains (observed directly at autopsy) without manifesting dementia during life. The resilient response of these individuals to the gradual accumulation of plaques and tangles has potential implications for assessing an individual's risk of AD and for the development of interventions aimed at preserving cognition.

Alzheimer-like pathology in the parietal cortex and hippocampus of aged donkeys

Neurodegenerative disorders are gaining ever more importance in ageing populations of animals and people. Altered insulin signaling and type II diabetes have been linked to the development of Alzheimer's disease (AD) in humans and AD-like neurodegeneration in other long-lived animals. Donkeys are unusual amongst domestic species for their exceptional longevity and are additionally predisposed to abnormalities of insulin metabolism similar to those found in humans. In this study, the parietal lobe and hippocampus of 13 aged (>30 years) and 2 younger control donkeys were evaluated immunohistologically for the presence, distribution, and frequency of neurofibrillary tangles (NFT) and amyloid plaques (AP); the characteristic lesions of AD. AP were in parietal cortices of 9 donkeys, with a predilection for deep sulci, and NFT-like structures were observed in 7 donkeys, primarily within cortical areas. No changes were observed in the control donkeys. This represents the first identification of both AP and NFT in equids and is a stimulus for future work assessing their metabolic status in parallel.

P2X7 receptor-specific radioligand 18F-FTTM for atherosclerotic plaque PET imaging.

P2X7 receptors have been considered as a promising biomarker for vulnerable atherosclerotic plaques, which are highly expressed by that instability-associated factors such as macrophages. Thus, we aim to investigate the feasibility of using specific P2X7-targeted 18F-labeled tracer 18F-FTTM ((2-chloro-3-[18F]fluorophenyl)[1,4,6,7-tetrahydro-1-(2-pyrimidinyl)-5H-1,2,3-triazolo[4,5-c]pyridin-5-yl]methanone) for PET study of vulnerable atherosclerotic plaques identification. The radioligand 18F-FTTM was achieved based on the copper-mediated radiofluorination of arylstannane. In vitro and in vivo experiments were performed to verify the biochemical properties. Dynamic 18F-FTTM Micro-PET/CT imaging was performed for 1h on ApoE-/- mice (10, 20, 30weeks on high-fat diet) and wild-type C57BL/6J mice on normal diet. Ex vivo PET imaging was conducted to verify the specificity of the radioligand. Serum inflammatory cytokines, lipids, and lipoproteins profiles were detected by ELISA. The lipid distribution and morphology of plaques were evaluated by Oil Red O, HE, Masson, and immunofluorescence stainings. 18F-FTTM was afforded with decay-corrected radiochemical yields of 5-10%, specific activity of 269-320MBq/nmol (n = 8, EOS), and radiochemical purity of above 99%. 18F-FTTM showed excellent stability in vitro, rapid blood clearance in mice, good affinity to RAW264.7 cells. We observed an increase in both in vivo and ex vivo imagings as disease progressed, and the imaging signatures correlated with histopathological features. Furthermore, compared with 18F-FDG imaging, the SUVmax values of 18F-FTTM at the aortic arch of ApoE-/- mice of high-fat feeding for 20 and 30weeks were 43% and 53% higher than those of the control group, respectively. We innovatively apply a new type P2X7-targeted PET probe (18F-FTTM) to identify vulnerable atherosclerotic plaques, to detect the inflammatory response of atherosclerosis, and to provide a powerful non-invasive method for the diagnosis of atherosclerotic lesions and new drug screening for accurate treatment.

Research Progress of Percutaneous Interventional Therapy For Bifurcation Lesions of Coronary Heart Disease

Compared with non-bifurcation lesions, even if the new generation of percutaneous coronary intervention (PCI) technology is used to treat coronary bifurcation lesions, the incidence of adverse cardiovascular events is still higher. The evaluation of related clinical data and computer virtual modeling before surgery can guide the implementation of bifurcation PCI in a more precise manner. The new understanding of bifurcation PCI may further improve the clinical prognosis and outcome of patients with bifurcation disease. This review aims to summarize the assessment methods of PCI for coronary heart disease non-left main bifurcation disease and the treatment plan supported by clinical evidence. The treatment plan depends on three parameters: the diameter of the three parts of the bifurcation lesion; the length of the lesion and plaque distribution; and the angle of the bifurcation. To this day, the best technique for PCI for bifurcation lesions is still controversial, and a personalized approach using temporary collateral stent implantation schemes seems to be suitable for 75% to 95% of patients. For more complex bifurcation lesions, it may be necessary to use two stents at the same time. More and more evidence supports the practicability of the DK-crush technique.

Standard-Dose Atorvastatin Treatment in Patients With Symptomatic Middle Cerebral Artery Atherosclerotic Stenosis: A Vessel Wall Magnetic Resonance Imaging Study.

Background and Purpose: Ischemic stroke can be caused by atherosclerotic lesions of the middle cerebral artery (MCA). Some studies have described the effects of statin treatment on carotid artery plaques, but little is known about the effects of statin treatment on MCA plaques. The purpose of this study was to validate the efficacy of standard-dose atorvastatin (20 mg/day) in patients with symptomatic MCA atherosclerotic stenosis (SMAS) in northern China.Materials and Methods: This study is a prospective, single-arm, single-center, 12-month follow-up observational study monitoring imaging, and clinical outcomes of standard-dose atorvastatin treatment among patients with SMAS. The primary outcomes were changes in vessel wall magnetic resonance imaging (VWMRI) and serum lipid profiles before and after (1, 3, 6, and 12 months) statin treatment.Results: A total of 46 patients were recruited for this study, and 24 patients completed the follow-up. During the follow-up period, serum non-high-density lipoprotein cholesterol concentrations gradually decreased in the patients. Fourteen patients (54.33%) had a reversal of MCA plaques and 10 patients (41.67%) had no significant progression of MCA plaques and remained stable at the follow-up endpoint. At the 12 months follow-up time-point, the treatment did not reverse vascular remodeling or change the shape and distribution of plaques. Altered serum low-density lipoprotein cholesterol (LDL-C) concentrations in patients were strongly associated with plaque reversal.Conclusion: Vessel wall magnetic resonance imaging could accurately characterize changes in MCA plaques after lipid-lowering therapy. Standard-dose atorvastatin treatment could stabilize and reverse plaques in northern Chinese patients with SMAS.

A New Tool for the Analysis of the Effect of Intracerebrally Injected Anti-Amyloid-β Compounds.

Background:A wide range of techniques has been developed over the past decades to characterize amyloid-β (Aβ) pathology in mice. Until now, no method has been established to quantify spatial changes in Aβ plaque deposition due to targeted delivery of substances using ALZET® pumps.Objective:Development of a methodology to quantify the local distribution of Aβ plaques after intracerebral infusion of compounds.Methods:We have developed a toolbox to quantify Aβ plaques in relation to intracerebral injection channels using Zeiss AxioVision® and Microsoft Excel® software. For the proof of concept, intracerebral stereotactic surgery was performed in 50-day-old APP-transgenic mice injected with PBS. At the age of 100 days, brains were collected for immunhistological analysis.Results:The toolbox can be used to analyze and evaluate Aβ plaques (number, size, and coverage) in specific brain areas based on their location relative to the point of the injection or the injection channel. The tool provides classification of Aβ plaques in pre-defined distance groups using two different approaches.Conclusion:This new analytic toolbox facilitates the analysis of long-term continuous intracerebral experimental compound infusions using ALZET® pumps. This method generates reliable data for Aβ deposition characterization in relation to the distribution of experimental compounds.

Quantifying patterns of pathology: A characterization of the 3D spatial distribution of tau tangles and amyloid plaques in Alzheimer’s disease using multi‐modal image registration with a scattering transform

AbstractBackgroundVolumetric measures of MRI scans have consistently shown medial temporal lobe (MTL) atrophy in individuals across the spectrum of AD. However, these measures are not considered to be specific for AD, partly because a direct link to tau and amyloid pathology has not been demonstrated (Jack et. al, 2018). To address this limitation, we developed multi‐modal image registration and analysis tools to integrate neuropathological data from 2D histology images with 3D postmortem MRI images in the same brain region, in order to quantify the density of tangles and plaques.MethodsWe imaged tissue excised from the MTL at 0.125 mm resolution with an 11T MR scanner (fig 1a) and manually segmented it into subregions (fig 1b). We sliced the tissue into 10um thick sections, 1mm apart, and digitally imaged them with a light microscope after staining for amyloid (6E10) or tau (PHF‐1) (fig 1c). Locations of tangles and plaques on histology were estimated with a deep convolutional neural network (UNET) trained on a smaller set of annotated data (fig 1d). To align histology images with the MRI images, we first computed scattering transforms of histology to capture high resolution textural information (fig 1e). This was then used to find both optimal spatial and intensity profile transformations between the two imaging modalities (fig 1f). We rigidly aligned MRI images to the Mai Paxinos atlas for interpretability.ResultsWe localized tau tangles and amyloid plaques from histology sections of a person with severe AD, and in corresponding 3D MRI images of the brain tissue from the same individual. We quantified density of particles per region. Initial findings demonstrated the highest amount of tau in the entorhinal cortex, subiculum, and CA1 (fig 2) compared to other subregions in the MTL, consistent with Braak staging. No obvious differential distribution of amyloid was observed.ConclusionOur detailed localization of tangles and plaques in 3D offers the opportunity to study spatial distribution of pathology within brain regions among patients that span the spectrum of disease, which will foster more robust comparison with MRI atrophy, and potentially shed new light on the progression of AD.

Intermittent hypoxia treatment alleviates memory impairment in the 6-month-old APPswe/PS1dE9 mice and reduces amyloid beta accumulation and inflammation in the brain

BackgroundAlzheimer’s disease (AD) is a progressive, degenerative, and terminal disease without cure. There is an urgent need for a new strategy to treat AD. The aim of this study was to investigate the effects of intermittent hypoxic treatment (IHT) on cognitive functions in a mouse model of AD and unravel the mechanism of action of IHT.MethodsSix-month-old APPswe/PS1dE9 (APP/PS1) male mice were exposed to hypoxic environment (14.3% O2) 4 h/day for 14 days or 28 days. Cognitive functions were measured by Morris water maze test after either 14 days or 42 days of interval. Thereafter the distribution of amyloid plaque and microglial activation were determined by mouse brain immunohistochemistry, while the amyloid beta (Aβ) and inflammatory cytokines were measured by ELISA and Western Blot. Microarray was used for studying gene expressions in the hippocampus.ResultsIHT for 14 days or 28 days significantly improved the spatial memory ability of the 6-month-old APP/PS1 mice. The memory improvement by 14 days IHT lasted to 14 days, but not to 42 days. The level of Aβ plaques and neurofilament accumulations was reduced markedly after the IHT exposure. IHT reduced the pro-inflammatory cytokines IL-1β, IL-6 levels, and β-secretase cleavage of APP processing which implies reduced Aβ production. Microarray analysis revealed a large number of genes in the hippocampus were significantly altered which are known to be metabolism-regulated genes.ConclusionsThis study provides evidence of the beneficial effect of IHT on the progression of AD by alleviating memory impairment, reducing Aβ accumulation and inflammation in the brain. IHT can be developed as a novel measure to relieve the progression of AD by targeting multiple pathways in the AD pathogenesis.

The Atherosclerotic Profile of a Young Symptomatic Population between 19 and 49 Years: Coronary Computed Tomography Angiography or Coronary Artery Calcium Score?

(1) Background: Whether coronary computed tomography angiography (CTA) or the coronary artery calcium score (CACS) should be used for diagnosis of coronary heart disease, is an open debate. The aim of our study was to compare the atherosclerotic profile by coronary CTA in a young symptomatic high-risk population (age, 19–49 years) in comparison with the coronary artery calcium score (CACS). (2) Methods: 1137 symptomatic high-risk patients between 19–49 years (mean age, 42.4 y) who underwent coronary CTA and CACS were stratified into six age groups. CTA-analysis included stenosis severity and high-risk-plaque criteria (3) Results: Atherosclerosis was more often detected based on CTA than based on CACS (45 vs. 27%; p < 0.001), 50% stenosis in 13.6% and high-risk plaque in 17.7%. Prevalence of atherosclerosis was low and not different between CACS and CTA in the youngest age groups (19–30 y: 5.2 and 6.4% and 30–35 y: 10.6 and 16%). In patients older than >35 years, the rate of atherosclerosis based on CTA increased (p = 0.004, OR: 2.8, 95%CI:1.45–5.89); and was higher by CTA as compared to CACS (34.9 vs. 16.7%; p < 0.001), with a superior performance of CTA. In patients older than 35 years, stenosis severity (p = 0.002) and >50% stenosis increased from 2.6 to 12.5% (p < 0.001). High-risk plaque prevalence increased from 6.4 to 26.5%. The distribution of high-risk plaque between CACS 0 and >0.1 AU was similar among all age groups, with an increasing proportion in CACS > 0.1 AU with age. A total of 24.9% of CACS 0 patients had coronary artery disease based on CTA, 4.4% > 50% stenosis and 11.5% had high-risk plaque. (4) Conclusions: In a symptomatic young high-risk population older than 35 years, CTA performed superior than CACS. In patients aged 19–35 years, the rate of atherosclerosis was similar and low based on both modalities. CACS 0 did not rule out coronary artery disease in a young high-risk population.

Abstract 11412: Methyltransferase Smyd2 Mediate Atherosclerotic Plaque Calcification

Introduction: Clinical manifestation of atherosclerosis is marked by calcification of vasculature, including the expression of mineralization regulating proteins (Sox9, Msx2, and Runx2) by vascular smooth muscle cells (VSMCs). This pathogenic remodeling of VSMCs into osteochondrogenic cell types is accompanied by increased proliferation, migration, and secretion of extracellular matrix proteins. This study aimed to determine the spatiotemporal role of SMYD2 in atherosclerotic plaque progression and calcification. Methods: SMC-specific SMYD2 knockout was generated in ApoE -/- mice (SMYD2 ΔSMC ApoE -/- ). Age and body weight-matched mice were fed with Western diet (WD) for 18 or 26 weeks. The distribution of atherosclerotic plaque was examined by En-face Oil-Red-O staining (ORO) of freshly collected aorta. Atherosclerotic plaque burden was determined by Hematoxylin &amp; Eosin (H&amp;E) staining. Collagen content and calcification of atherosclerotic plaque were determined by Masson's trichrome staining and von Kossa staining, respectively. The calcification-regulatory genes (MGP1, AGG and transcription factors SOX9, MSX2, BMP2, and RUNX2) in the aorta were analyzed by RT-qPCR. Results: SMC-specific deletion of SMYD2 protected mice from atherosclerotic plaque calcification. En-face ORO and H&amp;E analysis of Brachiocephalic artery demonstrated a significant decrease in ORO positive area, total plaque size, and necrotic core area in SMYD2 ΔSMC ApoE -/- mice as compared to ApoE-/- mice, with no change in the distribution of collagen fibers. Von Kossa staining showed hydroxyapatite depots at the medial lining of the vasculature (microcalcification) in ApoE -/- mice fed with 18-week Western diet, while a smaller depot of macrocalcification was observed in SMYD2 ΔSMC ApoE -/- mice compared with ApoE -/- mice when fed with 26-week WD. mRNA analysis of key calcification transcription factors showed significant suppression of SOX9 and MSX2 genes in aortas of SMYD2 ΔSMC ApoE -/- mice compared with ApoE -/- mice, with downward trends of BMP2 and RUNX2 in both 18- or 26-week WD. Conclusion: SMYD2 ablation attenuates atherosclerotic plaque formation and calcification, suggests targeting SMYD2 can be a potential therapeutic strategy for atherosclerosis.