Induction of Atherosclerotic Plaques Through Activation of Mineralocorticoid Receptors in Apolipoprotein E-deficient Mice
September 26th, 2018
9.8K views
We describe a protocol to induce atherosclerosis in the aortic root of ApoE-/- mice fed with an atherogenic diet, through a continuous release of aldosterone. Methods to characterize plaque composition are also described.
Overview
This article describes a protocol for inducing atherosclerosis in the aortic root of ApoE -/- mice through continuous aldosterone release. The method allows for efficient characterization of plaque composition.
Key Study Components
Area of Science
- Neuroscience
- Cardiovascular Biology
- Pathophysiology
Background
- Atherosclerosis is a major cardiovascular disease.
- ApoE -/- mice are commonly used to study atherosclerosis.
- Aldosterone is known to influence plaque development.
- Understanding early atherosclerosis can lead to better therapeutic strategies.
Purpose of Study
- To establish a reliable method for inducing atherosclerosis in mice.
- To investigate the role of aldosterone in plaque formation.
- To provide a visual demonstration of the protocol for better understanding.
Methods Used
- Induction of atherosclerosis via continuous aldosterone release.
- Use of a mini-pump for controlled delivery of aldosterone.
- Characterization of plaque composition through various techniques.
- Visual demonstration of the procedure by a trained scientist.
Main Results
- Aldosterone efficiently induces plaque development in adult mice.
- The method allows for rapid assessment of atherosclerosis progression.
- Visual aids enhance understanding of complex technical steps.
- Demonstration by an experienced staff scientist improves learning outcomes.
Conclusions
- This protocol is a valuable tool for studying atherosclerosis.
- It provides insights into the pathophysiology of early plaque formation.
- Future studies can build on this method to explore therapeutic interventions.
Frequently Asked Questions
What is the significance of using ApoE -/- mice?
ApoE -/- mice are a standard model for studying atherosclerosis due to their susceptibility to plaque formation.
How does aldosterone influence atherosclerosis?
Aldosterone promotes inflammation and lipid accumulation, contributing to plaque development.
Why is a visual demonstration important?
Visual demonstrations help clarify complex procedures that may be difficult to learn through text alone.
What are the main advantages of this method?
The method is efficient and allows for rapid induction of atherosclerosis, facilitating timely research.
What techniques are used to characterize plaque composition?
Various histological and biochemical techniques are employed to analyze plaque characteristics.
Who conducted the demonstration of the protocol?
Caterina Mammi, a staff scientist, conducted the demonstration to ensure proper technique.
Executive Industry Relevance
This protocol enables rapid induction of atherosclerotic plaques in ApoE-deficient mice via aldosterone infusion, providing a disease-relevant system for studying early atherogenesis. The model supports mechanistic de-risking of anti-atherogenic targets by generating lipid- and macrophage-rich plaques within four weeks. It offers predictive value for target validation and preclinical screening in cardiovascular drug discovery pipelines.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of mineralocorticoid receptor signaling in atherosclerotic plaque formation.
- Operational Value: Provides a rapid, reproducible model for testing target engagement and pathway modulation.
- Strategic Value: Supports hypothesis-driven validation of novel pharmacological targets in atherosclerosis.
Screening & Assay Development
- Scientific Value: Generates quantifiable lipid and inflammatory outputs via Oil Red O and MAC-3 staining for compound screening.
- Operational Value: Standardizes plaque phenotyping at the aortic root level for consistent readouts across studies.
- Strategic Value: Facilitates assay-ready systems for evaluating anti-inflammatory and lipid-lowering candidates.
Translational & Preclinical Research
- Scientific Value: Models human atherosclerotic plaque phenotype with lipid accumulation and macrophage infiltration.
- Operational Value: Enables longitudinal assessment of plaque progression and therapeutic intervention timing.
- Strategic Value: Informs go/no-go decisions by linking target modulation to plaque phenotype changes.
Pipeline & Workflow Integration
The method fits within the cardiovascular discovery continuum from target validation to preclinical efficacy testing, enabling iterative design-make-test cycles.
- Discovery Biology: Supports mechanistic studies of aldosterone-driven endothelial dysfunction and vascular inflammation.
- Screening: Delivers standardized, quantifiable lesion metrics for compound effect comparison.
- Analytics: Provides histological and immunohistochemical endpoints for objective plaque characterization.
- Translational Research: Bridges discovery to preclinical validation through disease-relevant plaque morphology.
- Enterprise Reuse: Establishes a reusable platform for multiple target classes in atherosclerosis research.
Operational & Enterprise Impact
- Scientific Value: Enhances target confidence by modeling human-relevant plaque inflammation and lipid loading.
- Operational Value: Ensures reproducibility through standardized surgical, perfusion, and sectioning protocols.
- Strategic Value: Reduces biological attrition by enabling early mechanistic de-risking in vivo.
- Portfolio Impact: Improves risk-adjusted prioritization of cardiovascular candidates via phenotypic anchoring.
Implementation Considerations
- Requires expertise in microsurgical pump implantation and tissue handling.
- Dependent on infusion pump technology and sterile surgical infrastructure.
- Necessitates histology and imaging resources for Oil Red O, MAC-3, and collagen staining.
- Limited to ApoE-deficient models; not generalizable to wild-type or other strains without validation.
- OCT embedding step critical for antigen preservation and section quality in immunohistochemical analysis.
Biopharma FAQs
Why does aldosterone infusion accelerate plaque formation in ApoE-/- mice?
Aldosterone promotes lipid accumulation and macrophage infiltration in the aortic root, driving early atherosclerotic lesion development within four weeks. This models human-relevant pathophysiology for target validation studies.
How does Oil Red O staining enable quantitative assessment of atherosclerotic burden?
Oil Red O staining neutralizes lipid content in plaque sections, allowing densitometric quantification of atherosclerotic burden at the aortic root level. This provides a standardized output for comparing treatment effects.
What does MAC-3 staining reveal about plaque phenotype in this model?
MAC-3 staining identifies macrophage content within atherosclerotic plaques, indicating inflammatory activity and plaque instability. Increased MAC-3 signal reflects aldosterone-driven inflammation in ApoE-/- mice.
Why is perfusion with DPBS and formalin necessary before tissue harvesting?
Perfusion clears intravascular blood and fixes tissue morphology, ensuring accurate plaque visualization and preventing artifact during sectioning. This step preserves anatomical integrity for reliable aortic root analysis.
How does OCT embedding support immunohistochemical detection in aortic root sections?
OCT embedding preserves tissue antigenicity and enables high-quality cryosectioning, facilitating detectability of targets like MAC-3 and collagen. This is critical for consistent immunohistochemical readouts across experimental groups.
Chapters in this video
0:04
Title
0:45
Osmotic Pump Filling and Implantation
2:38
Heart Dissection
4:03
Aortic Root Sectioning and Oil Red O Neutral Fat Staining
5:47
Results: Evaluation of the Aortic Root Phenotype in Aldosterone-induced Atherosclerosis in Apolipoprotein-E Knockout (ApoE -/-) Mice
6:28
Conclusion
