Real-Time Assessment of Spinal Cord Microperfusion in a Porcine Model of Ischemia/Reperfusion
December 10th, 2020
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Spinal cord microcirculation plays a pivotal role in spinal cord injury. Most methods do not allow real-time assessment of spinal cord microcirculation, which is essential for the development of microcirculation-targeted therapies. Here, we propose a protocol using Laser-Doppler-Flow Needle probes in a large animal model of ischemia/reperfusion.
Overview
This protocol provides a reproducible method for real-time assessment of spinal cord microcirculation, crucial for developing targeted therapies. It allows evaluation of therapeutic approaches under ischemia/reperfusion conditions in a large animal model.
Key Study Components
Area of Science
- Neuroscience
- Microcirculation
- Spinal Cord Injury
Background
- Spinal cord microcirculation is vital for spinal cord injury recovery.
- Real-time assessment methods are lacking in current research.
- Existing techniques do not adequately evaluate microcirculation during ischemia/reperfusion.
- This study aims to fill that gap with a new protocol.
Purpose of Study
- To assess spinal cord microcirculation in real-time.
- To evaluate therapeutic approaches for spinal cord injuries.
- To study ischemia/reperfusion conditions effectively.
Methods Used
- Use of Laser-Doppler-Flow Needle probes.
- Large animal model (three-month-old pig).
- Assessment of cerebrospinal fluid pressure and macrohemodynamics.
- Minimally invasive technique that is easy to learn.
Main Results
- Successful real-time monitoring of spinal cord microcirculation.
- Ability to assess therapeutic interventions effectively.
- Demonstrated procedure by specialists in anesthesiology.
- Potential for broader applications in spinal cord injury research.
Conclusions
- The protocol offers a novel approach to studying spinal cord microcirculation.
- It enhances the understanding of therapeutic strategies for spinal injuries.
- Future research can build on this method for improved outcomes.
Frequently Asked Questions
What is the significance of spinal cord microcirculation?
Spinal cord microcirculation is crucial for recovery after injury, influencing healing and therapeutic outcomes.
How does this protocol improve existing methods?
It allows for real-time assessment, which is essential for evaluating therapies during ischemia/reperfusion.
What animal model is used in this study?
A three-month-old 40-kilogram pig is used as the large animal model.
Who demonstrates the procedure?
Dr. Christoph Behem and Dr. Till Friedheim, along with resident Michael Graessler, demonstrate the procedure.
Is the technique invasive?
No, it is a minimally invasive technique that is easy to learn.
What additional parameters can be assessed with this method?
Cerebrospinal fluid pressure and macrohemodynamics can be assessed in parallel.
Executive Industry Relevance
Real-time assessment of spinal cord microcirculation enables mechanistic de-risking in preclinical models of ischemia/reperfusion injury. This capability supports target validation by providing quantitative, dynamic readouts of tissue perfusion under controlled ischemic conditions. The protocol enhances predictive confidence in evaluating neuroprotective or vasoactive compounds prior to lead identification stages.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses related to spinal cord perfusion pathways.
- Operational Value: Provides functional target validation through direct measurement of microcirculatory responses to ischemic challenge.
- Predictive Value: Supports portfolio triage by identifying compounds that preserve or restore microperfusion during reperfusion.
Screening & Assay Development
- Assay Readiness: Prepares validated biological systems for compound screening by establishing baseline and ischemic microcirculatory responses.
- Quantitative Output: Delivers real-time laser-Doppler flux measurements that enable dose-response analysis of vasoactive agents.
- Reproducibility: Standardized probe placement and hemodynamic monitoring ensure consistent data across experimental groups.
Translational & Preclinical Research
- Disease Relevance: Uses a porcine model of aortic cross-clamping to simulate clinical ischemia/reperfusion conditions relevant to spinal cord injury.
- Translational Continuity: Correlates laser-Doppler readings with fluorescent microsphere analysis, validating the method against established microcirculatory benchmarks.
- Risk-Adjusted Advancement: Enables go/no-go decisions based on microcirculatory recovery profiles, reducing late-stage biological risk in CNS-targeted programs.
Pipeline & Workflow Integration
The method fits within the discovery continuum from target validation through preclinical evaluation, particularly for CNS ischemia and reperfusion injury models.
- Discovery Biology: Supports hypothesis testing of neurovascular mechanisms and pathway modulation in ischemic spinal cord tissue.
- Screening: Enables assessment of compound effects on microcirculatory stability and recovery, critical for vasoprotective lead identification.
- Analytics: Provides continuous, real-time flux data that allows comparison of perfusion dynamics across ischemic and reperfusion phases.
- Translational Research: Aligns with biomarker strategies by linking functional perfusion outcomes to histopathological and microsphere validation.
- Enterprise Reuse: Establishes a reusable large animal platform for iterative testing of microcirculation-targeted therapeutics across multiple projects.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic ambiguity by directly linking ischemic insult to microcirculatory dynamics in a clinically relevant model.
- Operational Value: Ensures standardization through reproducible probe placement, cerebrospinal fluid drainage, and hemodynamic monitoring.
- Strategic Value: Improves capital efficiency by enabling early detection of ineffective compounds, reducing failure in later preclinical stages.
- Portfolio Impact: Facilitates risk-adjusted prioritization of candidates based on demonstrated microcirculatory preservation or recovery.
Implementation Considerations
- Requires expertise in large animal neurosurgical techniques and spinal cord anatomy for accurate probe placement.
- Dependent on laser-Doppler instrumentation, cerebrospinal fluid drainage systems, and hemodynamic monitoring infrastructure.
- Necessitates cross-functional standardization between surgery, anesthesia, and data acquisition teams to maintain signal integrity.
- Adaptation to other models (e.g., rodent or non-human primate) would require validation of probe size, insertion depth, and signal stability.
- Practical limitations include the technical skill required to avoid spinal cord injury during probe insertion, which could confound perfusion measurements.
Biopharma FAQs
Why does real-time microcirculatory measurement matter for target validation?
Real-time measurement allows researchers to observe dynamic changes in spinal cord perfusion during ischemia and reperfusion, providing direct evidence of target engagement by vasoactive or neuroprotective compounds. This supports target validation by linking mechanism to functional tissue-level outcomes under pathophysiologically relevant conditions.
How does isolation of the spinal cord microcirculation variable support discovery pipeline decisions?
By measuring microcirculatory flux independently of macrohemodynamics, the protocol isolates the effect of interventions on tissue-level perfusion, enabling clearer interpretation of compound activity. This independent variable isolation helps de-risk targets by distinguishing true microcirculatory effects from systemic hemodynamic changes.
What quantitative dependent variable measurements enable compound evaluation in this model?
Laser-Doppler flux provides a continuous, quantitative readout of spinal cord microcirculatory blood flow, allowing assessment of flow reduction during ischemia and recovery during reperfusion. These measurements enable dose-response analysis and comparison of compound effects on microcirculatory stability.
Why do replication requirements matter for cross-functional collaboration in this protocol?
Replication ensures consistent probe placement, signal stability, and hemodynamic conditions across experiments, which is essential for reliable data sharing between surgical, pharmacological, and analytical teams. Standardized replication supports reproducibility and builds confidence in preclinical go/no-go decisions.
What statistical analysis capabilities are required before implementing this method in a discovery setting?
Implementation requires the ability to perform time-series analysis of laser-Dopler flux data, compare ischemic and reperfusion phases using appropriate parametric or non-parametric tests, and correlate microcirculatory outcomes with histopathological or microsphere validation data. These capabilities are essential for drawing mechanistic conclusions from perfusion measurements.
