A Large Animal Model for Pulmonary Hypertension and Right Ventricular Failure: Left Pulmonary Artery Ligation and Progressive Main Pulmonary Artery Banding in Sheep
July 15th, 2021
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This manuscript describes the surgical technique and experimental approach to develop severe right ventricular pressure overload to model their adaptive and maladaptive phenotypes.
Overview
This manuscript describes a large animal model for studying right ventricular adaptation and failure, which is crucial for developing RV-targeted therapeutics for pulmonary hypertension. The model allows for controlled increases in right ventricular afterload, providing a unique approach to titrate RV adaptation.
Key Study Components
Area of Science
- Cardiovascular physiology
- Animal models
- Pulmonary hypertension
Background
- Right ventricular pressure overload is a significant factor in pulmonary hypertension.
- Understanding RV adaptation and failure is essential for therapeutic development.
- Previous models lacked control over RV phenotype adaptation.
- This study introduces a novel surgical technique for this purpose.
Purpose of Study
- To develop a model that simulates severe right ventricular pressure overload.
- To investigate adaptive and maladaptive phenotypes of the right ventricle.
- To facilitate the development of targeted therapies for pulmonary hypertension.
Methods Used
- Surgical procedure for pulmonary artery banding demonstrated by Dr. Matthew Bacchetta and surgical fellows.
- Progressive increase of right ventricular afterload to assess adaptation.
- Large animal model to ensure relevance to human physiology.
- Controlled experimental design to evaluate RV responses.
Main Results
- Successful implementation of the pulmonary artery banding technique.
- Establishment of a model that allows for titration of RV adaptation.
- Demonstration of the model's potential for studying RV failure.
- Insights into the adaptive and maladaptive responses of the right ventricle.
Conclusions
- The developed model provides a novel approach to studying right ventricular adaptation.
- This research is vital for advancing therapies for pulmonary hypertension.
- Future studies can leverage this model to explore RV-targeted interventions.
Frequently Asked Questions
What is the significance of right ventricular adaptation?
Right ventricular adaptation is crucial for managing pressure overload conditions like pulmonary hypertension, impacting treatment strategies.
Who conducted the surgical procedure?
The surgical procedure was conducted by Dr. Matthew Bacchetta and his team of surgical fellows.
How does this model differ from previous ones?
This model allows for controlled increases in right ventricular afterload, which was not possible in previous large animal models.
What are the potential applications of this research?
The research can lead to the development of RV-targeted therapeutics for treating pulmonary hypertension.
What is the main goal of the study?
The main goal is to create a model that accurately simulates severe right ventricular pressure overload for research purposes.
What techniques are used in this study?
The study employs surgical techniques for pulmonary artery banding and controlled experimental design to assess RV responses.
Executive Industry Relevance
This large animal model enables controlled titration of right ventricular afterload to study adaptive and maladaptive phenotypes in pulmonary hypertension. It provides a translationally relevant platform for evaluating RV-targeted therapeutics and mechanistic de-risking in preclinical development. The ability to modulate disease severity supports risk-adjusted decision-making in early discovery and lead optimization phases.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses by modeling progressive RV pressure overload and phenotypic transitions.
- Operational Value: Supports functional target validation through measurable RV pressure, wall thickness, and septal bowing as functional readouts.
- Predictive Value: Facilitates preclinical triage by distinguishing adaptive from maladaptive RV responses based on SvO2 trends and hemodynamic parameters.
Screening & Assay Development
- Assay Readiness: Establishes standardized, reproducible hemodynamic and oxygen saturation metrics for compound screening campaigns.
- Quantitative Outputs: Provides longitudinal SvO2, pulmonary artery cuff pressure, and RV pressure measurements as pharmacodynamic endpoints.
- Platform Utility: Enables reliable evaluation of compound effects on RV adaptation across graded disease severity levels.
Translational & Preclinical Research
- Disease Relevance: Recapitulates key features of human PH-RVF including RV dilation, hypertrophy, and interventricular septal bowing.
- Translational Continuity: Supports biomarker discovery through serial SvO2 and pressure monitoring correlating with RV decompensation.
- Mechanistic De-risking: Allows study of molecular pathways governing RV adaptation versus failure under controlled afterload conditions.
Pipeline & Workflow Integration
The model fits within the discovery continuum from target validation through preclinical efficacy testing, enabling iterative assessment of RV-targeted interventions.
- Discovery Biology: Supports hypothesis testing on RV remodeling pathways via controlled afterload increase and phenotypic monitoring.
- Screening: Delivers reproducible, quantitative hemodynamic and oxygenation readouts for compound effect comparison.
- Analytics: Generates time-series data on RV pressure, PA cuff pressure, and SvO2 to evaluate therapeutic impact on adaptation trajectories.
- Translational Research: Connects hemodynamic changes to clinical signs of decompensation such as pleural effusion and ascites.
- Enterprise Reuse: Functions as a tunable, reusable platform for multiple therapeutic modalities targeting RV stress response pathways.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in RV-targeted target selection by reducing mechanistic ambiguity in phenotype transition.
- Operational Value: Ensures standardization and reproducibility through defined surgical and banding protocols across study cohorts.
- Strategic Value: Improves go/no-go decisions by enabling early detection of maladaptive RV phenotypes before functional decline.
- Portfolio Impact: Supports risk-adjusted prioritization of compounds based on ability to preserve physiologic SvO2 and delay RV decompensation.
Implementation Considerations
- Requires expertise in large animal cardiovascular surgery and postoperative critical care management.
- Dependent on instrumentation for RV pressure transduction, vascular occlusion, and serial blood gas analysis.
- Necessitates cross-functional standardization between surgery, physiology, and animal care teams for consistent banding titration.
- Involves adaptation considerations when translating protocols across ovine, porcine, or bovine models due to anatomical variability.
- Limited by surgical complexity and resource intensity, restricting high-throughput application but supporting mechanistic depth.
Biopharma FAQs
Why does venous oxygen saturation matter for RV phenotype assessment?
SvO2 trends reflect the balance between RV output and pulmonary circulation, with values below 65% indicating decompensation and 70–80% representing compensated adaptation in this model.
How does progressive pulmonary artery banding enable RV phenotype titration?
Incremental increases in pulmonary artery cuff pressure allow graded elevation of RV afterload, permitting study of adaptive versus maladaptive responses over time.
What quantitative measurements enable detection of RV decompensation?
Declining SvO2, rising RV systolic pressure, and echocardiographic signs like septal bowing and wall thickness increase signal transition to failure.
Why are repeated hemodynamic measurements necessary for cross-functional collaboration?
Serial RV pressure, PA cuff pressure, and SvO2 data provide objective, shared endpoints for surgery, pharmacology, and pathology teams to align on phenotype timing.
What statistical capabilities are needed to interpret longitudinal RV adaptation data?
Repeated measures analysis is required to assess within-subject changes in RV pressure, SvO2, and cuff pressure across the 9-week banding period.
