Large scale serial two-photon microscopy to investigate local vascular changes in whole rodent brain models of Alzheimer's disease

2018 ◽  
Author(s):  
Patrick Delafontaine-Martel ◽  
Frédéric Lesage ◽  
Rafat Damseh ◽  
Joël Lefebvre ◽  
Alexandre Castonguay ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Vascular Changes ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Rodent Brain ◽  
Brain Models

scholarly journals Muramyl dipeptide mediated immunomodulation on monocyte subsets exerts therapeutic effects in a mouse model of Alzheimer’s disease

2020 ◽  
Author(s):  
Adham Fani Malekia ◽  
Giulia Cisbania ◽  
Marie-Michèle Plante ◽  
Paul Préfontaine ◽  
Nataly Laflamme ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Muramyl Dipeptide ◽  
Therapeutic Effects ◽  
Monocyte Subsets ◽  
Expression Levels ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Model Of Alzheimer’S Disease

Abstract Background Muramyl dipeptide (MDP) is a component derived from minimal peptidoglycan motif from bacteria and it is a ligand for the NOD2 receptor. Peripheral administration of MDP converts Ly6Chigh into Ly6Clow monocytes. Previously we have shown that Ly6Clow monocytes play crucial roles in the pathology of a mouse model of Alzheimer’s disease (AD). However, medications with mild immunomodulatory effects that solely target specific monocyte subsets, without triggering microglial activation are rare. Methods 3-months old APPswe/PS1 transgenic male mice and age-matched C57BL/6J mice were used for high frequency (2-times/week) over 6-months and low frequency (once a week) over a 3-months period of intraperitoneally MDP (10 mg/kg) administrations. Flow cytometry analysis of monocyte subsets in blood, behavioral and post mortem analyses were performed. Two-photon microscopy using APP/PS1/CX3CR1gfp/+ mice were conducted to study vascular Aβ clearance by Ly6Clow monocytes upon MDP administration.Results The treatment improved cognitive declines, increased expression levels of postsynaptic density protein 95 (PSD95) andlow density lipoprotein receptor-related protein 1 (LRP1), which are involved in synaptic plasticity and amyloid beta (Aβ) elimination, respectively. In addition, we found monocyte chemoattractant protein-1(MCP-1) levels significantly increased, whereas intercellular adhesion molecule-1(ICAM-1) significantly decreased and microglial marker (Iba1) did not change in treatment group compared to the control. In parallel, we discovered elevated cyclooxygenase-2 (COX2) expression levels in the treated group, which might be a positive factor for synaptic activity. Following MDP treatment, intravital two-photon microscopy demonstrated that Ly6Clow monocytes are recruited into the brain vasculature in APP but not wild type mice, and they are able to pick up Aβ peptides. Conclusions Our results demonstrate that MDP is beneficial in both the early phase and to some extent later phases of the pathology in the mouse model of AD. These data open the way for potential MDP-based medications for AD.

P4-027: Kinetics of dendritic structural plasticity in the living brain of an Alzheimer's disease mouse model acquired with two photon microscopy

2009 ◽  
Vol 5 (4S_Part_14) ◽  
pp. P439-P439
Author(s):  
Steffen Burgold ◽  
Martin Fuhrmann ◽  
Boris Schmidt ◽  
Hans Kretzschmar ◽  
Jochen Herms
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Structural Plasticity ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Kinetics Of

scholarly journals Whole brain vascular imaging in a mouse model of Alzheimer’s disease with two-photon microscopy

2018 ◽  
Vol 23 (07) ◽  
pp. 1 ◽  
Author(s):  
Patrick Delafontaine-Martel ◽  
Joel Lefebvre ◽  
Pier-Luc Tardif ◽  
Bernard I. Lévy ◽  
Philippe Pouliot ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Vascular Imaging ◽  
Whole Brain ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Model Of Alzheimer’S Disease

Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer’s Disease

2020 ◽  
Vol 17 (2) ◽  
pp. 141-157 ◽  
Author(s):  
Dubravka S. Strac ◽  
Marcela Konjevod ◽  
Matea N. Perkovic ◽  
Lucija Tudor ◽  
Gordana N. Erjavec ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Therapeutic Potential ◽  
Relevant Literature ◽  
Comprehensive Overview ◽  
Brain Functions ◽  
Specific Effects ◽  
And Behavior

Background: Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer’s disease. Objective: The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer’s disease. Method: PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. Results: We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer’s disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. Conclusion: Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer’s disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.

Structural Changes in Thalamic Nuclei Across Prodromal and Clinical Alzheimer’s Disease

2021 ◽  
pp. 1-11
Author(s):  
Adam S. Bernstein ◽  
Steven Z. Rapcsak ◽  
Michael Hornberger ◽  
Manojkumar Saranathan ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Structural Changes ◽  
Thalamic Nuclei ◽  
Medial Temporal Lobes ◽  
Cognitive Changes ◽  
Temporal Lobes ◽  
Medial Geniculate ◽  
Healthy Control

Background: Increasing evidence suggests that thalamic nuclei may atrophy in Alzheimer’s disease (AD). We hypothesized that there will be significant atrophy of limbic thalamic nuclei associated with declining memory and cognition across the AD continuum. Objective: The objective of this work was to characterize volume differences in thalamic nuclei in subjects with early and late mild cognitive impairment (MCI) as well as AD when compared to healthy control (HC) subjects using a novel MRI-based thalamic segmentation technique (THOMAS). Methods: MPRAGE data from the ADNI database were used in this study (n = 540). Healthy control (n = 125), early MCI (n = 212), late MCI (n = 114), and AD subjects (n = 89) were selected, and their MRI data were parcellated to determine the volumes of 11 thalamic nuclei for each subject. Volumes across the different clinical subgroups were compared using ANCOVA. Results: There were significant differences in thalamic nuclei volumes between HC, late MCI, and AD subjects. The anteroventral, mediodorsal, pulvinar, medial geniculate, and centromedian nuclei were significantly smaller in subjects with late MCI and AD when compared to HC subjects. Furthermore, the mediodorsal, pulvinar, and medial geniculate nuclei were significantly smaller in early MCI when compared to HC subjects. Conclusion: This work highlights nucleus specific atrophy within the thalamus in subjects with early and late MCI and AD. This is consistent with the hypothesis that memory and cognitive changes in AD are mediated by damage to a large-scale integrated neural network that extends beyond the medial temporal lobes.

scholarly journals Comparison of Amyloid β and Tau Spread Models in Alzheimer’s Disease

2018 ◽  
Vol 29 (10) ◽  
pp. 4291-4302 ◽  
Author(s):  
Hang-Rai Kim ◽  
Peter Lee ◽  
Sang Won Seo ◽  
Jee Hoon Roh ◽  
Minyoung Oh ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Amyloid Β ◽  
Brain Network ◽  
Amyloid Positron Emission Tomography ◽  
Local Spread ◽  
Positron Emission ◽  
Spread Model ◽  
Graph Theoretical Approach

Abstract Tau and amyloid β (Aβ), 2 key pathogenic proteins in Alzheimer’s disease (AD), reportedly spread throughout the brain as the disease progresses. Models of how these pathogenic proteins spread from affected to unaffected areas had been proposed based on the observation that these proteins could transmit to other regions either through neural fibers (transneuronal spread model) or through extracellular space (local spread model). In this study, we modeled the spread of tau and Aβ using a graph theoretical approach based on resting-state functional magnetic resonance imaging. We tested whether these models predict the distribution of tau and Aβ in the brains of AD spectrum patients. To assess the models’ performance, we calculated spatial correlation between the model-predicted map and the actual map from tau and amyloid positron emission tomography. The transneuronal spread model predicted the distribution of tau and Aβ deposition with significantly higher accuracy than the local spread model. Compared with tau, the local spread model also predicted a comparable portion of Aβ deposition. These findings provide evidence of transneuronal spread of AD pathogenic proteins in a large-scale brain network and furthermore suggest different contributions of spread models for tau and Aβ in AD.

scholarly journals A Large-scale Comparison of Cortical and Subcortical Structural Segmentation Methods in Alzheimer’s Disease: a Statistical Approach

2020 ◽  
Author(s):  
Jafar Zamani ◽  
Ali Sadr ◽  
Amir-Homayoun Javadi
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Automated Segmentation ◽  
Resonance Imaging ◽  
Brain Areas ◽  
Segmentation Methods ◽  
Magnetic Resonance Imaging Mri ◽  
Underlying Mechanisms ◽  
The Brain

AbstractBackgroundAlzheimer’s disease (AD) is a neurodegenerative disease that leads to anatomical atrophy, as evidenced by magnetic resonance imaging (MRI). Automated segmentation methods are developed to help with the segmentation of different brain areas. However, their reliability has yet to be fully investigated. To have a more comprehensive understanding of the distribution of changes in AD, as well as investigating the reliability of different segmentation methods, in this study we compared volumes of cortical and subcortical brain segments, using automated segmentation methods in more than 60 areas between AD and healthy controls (HC).MethodsA total of 44 MRI images (22 AD and 22 HC, 50% females) were taken from the minimal interval resonance imaging in Alzheimer’s disease (MIRIAD) dataset. HIPS, volBrain, CAT and BrainSuite segmentation methods were used for the subfields of hippocampus, and the rest of the brain.ResultsWhile HIPS, volBrain and CAT showed strong conformity with the past literature, BrainSuite misclassified several brain areas. Additionally, the volume of the brain areas that successfully discriminated between AD and HC showed a correlation with mini mental state examination (MMSE) scores. The two methods of volBrain and CAT showed a very strong correlation. These two methods, however, did not correlate with BrainSuite.ConclusionOur results showed that automated segmentation methods HIPS, volBrain and CAT can be used in the classification of AD and HC. This is an indication that such methods can be used to inform researchers and clinicians of underlying mechanisms and progression of AD.

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