A Murine Model of Hyperlipidemia-Induced Heart Failure with Preserved Ejection Fraction
March 29th, 2024
This protocol presents a detailed approach to replicating a murine model of hyperlipidemia-induced heart failure with preserved ejection fraction (HFpEF). The design combines the administration of adeno-associated virus 9-cardiac troponin T-low-density lipoprotein receptor (AAV9-cTnT-LDLR) and poloxamer-407 (P-407).
Our research aims at examining heart failure with preserved ejection fraction known as HFpEF, specifically investigating the effects of lipotoxicity. We seek to elucidate the intricate relationship between metabolic syndrome and lipotoxicity in driving HFpEF progression and uncover the underlying mechanisms driving HFpEF pathophysiology using this experimental mirroring model. Despite the rising prevalence and limited treatment options for HFpEF, it's pathophysiological mechanisms mainly related to metabolic syndrome remain poorly understood.
This model presents a unique opportunity to bridge this gap and potentially develop new therapies for HFpEF. Our model's most important advantage is its ability to mimic significant lipid mishandling observed in HFpEF patients. This mouse model offers valuable insights into the pathophysiology of HFpEF, especially cardiac metabolism.
Our findings under score the importance of fatty acid and cholesterol mishandling in cardiometabolic HFpEF. This model perfectly shows how fatty acid deprivation disrupts metabolism at different levels. It provide researchers with potential avenues to discover novel traps for HFpEF patients.
Here at the Shahada Laboratory, we will focus on translating this model into large animals. We will investigate questions related to the pathogenesis, sudden death and potential therapeutic interventions targeting lipotoxicity, inflammation and cardiac remodeling. Instructor[To Begin, thaw the viral vector stock vials on ice for 20 minutes and dilute the AAV particles in 100 microliters of DPBS.
Load the diluted AAV solution into a one milliliter syringe with a 28 to 30 gauge needle, avoiding air bubbles. Secure the anesthetized mouse in a tail illuminator restrainer, and use a gauze pad to clean the injection site with an antiseptic. Massage the tail with two fingers until the vein is observed.
Then inject the vector into the tail vein at a low angle and withdraw the needle. Using a finger apply pressure immediately to the injected site to stop the bleeding. To prepare Poloxamer 407, dissolve it in DPBS on a rotator overnight at four degrees Celsius in a biosafety cabinet.
Next, restrain the mouse manually under a fume hood positioning its head and body downwards. With an antiseptic, clean the injection site in the left lower quadrant of the abdomen, lateral to the midline. To inject P 407, insert the needle into the peritoneal cavity at an angle of 45 degrees or less.
After four weeks of hyperlipidemia induction, echocardiography revealed heart failure with preserved ejection fraction as intraventricular relaxation time was prolonged. An increased ratio between early mitral lean flow velocity and mitral annular early diastolic velocity, along with a decreased early to late diastolic trans mitral flow velocity was observed.
Overview
This protocol presents a detailed approach to replicating a murine model of hyperlipidemia-induced heart failure with preserved ejection fraction (HFpEF). The study investigates the effects of lipotoxicity and the relationship between metabolic syndrome and HFpEF progression.
Key Study Components
Area of Science
- Cardiovascular research
- Metabolic syndrome
- Heart failure pathophysiology
Background
- HFpEF is increasingly prevalent with limited treatment options.
- Pathophysiological mechanisms related to metabolic syndrome are poorly understood.
- This model mimics lipid mishandling observed in HFpEF patients.
- Insights into cardiac metabolism are crucial for developing new therapies.
Purpose of Study
- To elucidate mechanisms driving HFpEF pathophysiology.
- To explore the impact of fatty acid and cholesterol mishandling.
- To provide a model for potential therapeutic interventions targeting lipotoxicity.
Methods Used
- Administration of AAV9-cTnT-LDLR and poloxamer-407.
- Induction of hyperlipidemia in murine models.
- Echocardiography to assess heart function.
- Injection techniques for viral vectors and poloxamer.
Main Results
- Prolonged intraventricular relaxation time observed.
- Altered mitral flow velocity ratios indicating heart failure.
- Model effectively demonstrates lipid mishandling in HFpEF.
- Potential pathways for novel therapeutic strategies identified.
Conclusions
- This model provides valuable insights into HFpEF mechanisms.
- Fatty acid deprivation disrupts cardiac metabolism.
- Research may lead to improved therapies for HFpEF patients.
Frequently Asked Questions
Executive Industry Relevance
Hyperlipidemia-induced murine models of HFpEF provide a translational platform for dissecting the metabolic and lipotoxic drivers of diastolic dysfunction. This model enables mechanistic de-risking and target validation for cardiometabolic pathways implicated in heart failure with preserved ejection fraction. Its predictive value supports early-stage portfolio decisions and informs preclinical strategy for metabolic syndrome-related cardiac disease.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of lipotoxicity and metabolic syndrome as drivers of HFpEF pathogenesis.
- Supports functional target validation for lipid handling and cardiac metabolism pathways.
- Facilitates mechanistic de-risking by modeling human-relevant cardiac phenotypes.
- Provides a platform for hypothesis testing on metabolic and inflammatory contributors to HFpEF.
Screening & Assay Development
- Establishes a validated in vivo system for quantitative assessment of cardiac function and metabolic biomarkers.
- Supports reproducible measurement of diastolic dysfunction and preserved ejection fraction via echocardiography.
- Enables standardized evaluation of candidate interventions targeting lipid metabolism and cardiac remodeling.
- Prepares the groundwork for scalable compound screening in disease-relevant models.
Translational & Preclinical Research
- Aligns with disease-relevant endpoints such as fibrosis, cardiac ischemia, and sudden death observed in HFpEF patients.
- Provides continuity from discovery to preclinical validation for metabolic and inflammatory targets.
- Supports risk-adjusted advancement of therapeutic candidates addressing lipotoxicity-driven cardiac dysfunction.
- Facilitates biomarker alignment for translational studies in larger animal models.
Pipeline & Workflow Integration
This murine HFpEF model integrates into the discovery-to-preclinical continuum, enabling target validation, mechanistic studies, and translational biomarker development for cardiometabolic heart failure.
- Discovery Biology: Supports hypothesis testing on lipid mishandling and metabolic syndrome in cardiac dysfunction.
- Screening: Provides reproducible, quantitative cardiac and metabolic readouts for candidate evaluation.
- Analytics: Enables statistical comparison of diastolic function, fibrosis, and metabolic parameters across cohorts.
- Translational Research: Bridges murine findings to larger animal models and human disease phenotypes.
- Enterprise Reuse: Offers a reusable, standardized platform for cardiometabolic target and pathway interrogation.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in metabolic and lipotoxicity targets for HFpEF.
- Operational Value: Delivers standardized, reproducible in vivo assessments of cardiac and metabolic endpoints.
- Strategic Value: Informs go/no-go decisions for cardiometabolic programs and reduces late-stage biological risk.
- Portfolio Impact: Enables risk-adjusted prioritization of therapeutic candidates targeting HFpEF mechanisms.
Implementation Considerations
- Requires expertise in murine cardiovascular physiology and metabolic disease modeling.
- Demands access to echocardiography, telemetry, and biochemical analysis infrastructure.
- Necessitates cross-team standardization of phenotyping and data interpretation protocols.
- Adaptation to other strains or species may require protocol optimization.
- Model limitations include species-specific responses and translation to human HFpEF heterogeneity.
