Heterotopic and Orthotopic Tracheal Transplantation in Mice used as Models to Study the Development of Obliterative Airway Disease
January 20th, 2010
This video shows and compares two experimental models to study the development of obliterative airway disease (OAD) in mice, the heterotopic and orthotopic tracheal transplantation model.
Both the heterotopic and Orthotopic tracheal transplantations begin with the removal of the donor trachea for the heterotopic transplantation. An abdominal incision is made in the recipient and the intestines are placed on a glove. The donor trachea is placed into the center of the greater omentum and fixed by two stitches for the orthotopic transplantation.
After a cervical incision is made in the recipient, the trachea is freed of surrounding tissue and cut. Then the donor trachea is inserted between the two ends of the recipient trachea and the trachea are stitched together. Hi, I'm Sonya Refa.
I'm professor in Immunology and cardiac surgery in the Department of Cardiovascular Surgery at the University Heart Center in Hamburg. My laboratory is focusing on transplant immunology and stem cell immunobiology. Today we will introduce you to Moon Auto topic and topic transplantation model of the twig here.
Hello, I'm from the TSI lab. We are using the also topic and the heterotopic trachea transplantation mouse models to study the mechanisms behind the development of observative airway diseases. And I'm Carrie Wan, a student at Stanford University and a summer fellow in Drer's TSI Laboratory.
So let's get started. Before beginning this procedure shaved the cervical hair and disinfect the area using beta isod. Confirm that the donor mouse is completely anesthetized by a lack of the toe pinch reflex.
Under microscopic view, perform a midline cervical incision from the level of the larynx to the sternum. Remove the subcutaneous fat as well as the strap muscles to get a clear view of the trachea. Dissect the trachea from any surrounding tissues such as the esophagus, nerves, arteries, and connective tissue.
Remove the whole trachea from the larynx to the bifurcation. Flush the transplant trachea with cold saline and store the graft at four degrees Celsius. After confirming a lack of the toe pinch reflex in the anesthetized recipient mouse, shave the abdominal hair in a wide margin around the incision site and disinfect the area.
Using beta is Sedona and alcohol. Perform a median laparotomy and place the intestine into a moisture glove. Spread the greater omentum.
Carefully place the graft into the center and fixate it with two eight oh proline sutures. Fully cover the transplant with the greater omentum and fix the graft with a single eight o prolene suture. Relocate the intestines back into the abdomen.
Close up the incision in two layers, the abdominal wall and skin layer with continuous pattern seven O proline sutures. After confirming that the recipient mouse is fully anesthetized using IP applicated injection, anesthesia, shave and disinfect the cervical area as previously shown, perform a midline cervical incision from the level of the larynx to the sternum. Divide the thymus and strap muscles to visualize the entire laryn tracheal complex.
Carefully dissect the trachea from the surrounding tissues. Taking care to preserve the recurrent laryngeal nerves. Spread the corvus and divide the trachea.
Three rings coddle from the cricoid. The animal will maintain physiologic respiration via the tracheostomy. Ensure clean tracheal edges in the recipient as well as in the graft by dissecting the tracheas under microscopic view.
The graft is interposed between the recipient tracheal defects and oriented to maintain anatomic polarity using eight o proline sutures. Anastomosis the donor graft with the distal or mediastinal trachea. The posterior aspect of the anastomosis is performed in continuous running fashion.
The anterior aspect is then completed using interrupted sutures. Then remove any secretions from the airway. The proximal anastomosis is then completed in the same way as the distal one.
Perform the posterior aspect in continuous running fashion and the anterior aspect with interrupted sutures. Ensure integrity of the airway and adequate spontaneous breathing. Relocate the strap muscles and close the skin layer using six oh continuous pattern Vicryl sutures when the heterotopic transplanted trachea is recovered after 28 days and analyzed histologically by h and d staining 100%luminal obliteration is observed when the orthotopic transplanted trachea is recovered after 60 days and analyzed histologically by h and d staining, a maximal luminal obliteration of approximately 45%is achieved.
We have just shown you two different models to investigate the development of literative airway disease. The appropriate model should be chosen by the study hypothesis. Our lab favors the also topic one since the physiological airflow imitates the clinical setting.
So that's it. Thanks for watching and good luck with your experiments.
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Overview
This video shows and compares two experimental models to study the development of obliterative airway disease (OAD) in mice, the heterotopic and orthotopic tracheal transplantation model. The procedures for both models involve specific surgical techniques to transplant the donor trachea into the recipient.
Key Study Components
Area of Science
- Neuroscience
- Transplantation Biology
- Respiratory Diseases
Background
- Obliterative airway disease (OAD) is a significant complication in transplantation.
- Understanding the mechanisms of OAD can improve transplant outcomes.
- Animal models are essential for studying disease development and treatment strategies.
- Tracheal transplantation models provide insights into airway healing and disease progression.
Purpose of Study
- To compare the heterotopic and orthotopic tracheal transplantation models.
- To evaluate the development of OAD in these models.
- To enhance understanding of airway transplantation and its complications.
Methods Used
- Heterotopic transplantation involves abdominal incision and placement of the donor trachea in the greater omentum.
- Orthotopic transplantation requires a cervical incision to connect the donor trachea to the recipient's trachea.
- Both models utilize sutures to secure the trachea in place.
- Post-operative monitoring and assessment of airway disease development.
Main Results
- Both models successfully demonstrate the surgical techniques for tracheal transplantation.
- Comparative analysis reveals differences in OAD development between the two models.
- Insights gained can inform future research on airway diseases.
- Results contribute to the understanding of transplant-related complications.
Conclusions
- Both heterotopic and orthotopic models are valuable for studying OAD.
- Each model has unique advantages and limitations for research purposes.
- Further studies are needed to explore therapeutic interventions for OAD.
Frequently Asked Questions
Executive Industry Relevance
Obliterative airway disease (OAD) remains a major cause of graft failure and reduced long-term survival following lung transplantation, representing a critical unmet need in transplant immunology. Establishing reliable preclinical models that recapitulate human OAD pathology enables mechanistic de-risking of therapeutic strategies targeting fibroproliferative airway remodeling. The heterotopic and orthotopic murine tracheal transplantation models described provide complementary systems to evaluate airway healing, immune-mediated injury, and luminal obliteration, supporting target validation and lead identification in respiratory fibrosis and chronic rejection pathways.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses in airway fibrosis by modeling immune-mediated epithelial injury and subepithelial fibrosis analogous to human OAD.
- Operational Value: Provides a surgically standardized system to assess target engagement of anti-fibrotic or immunomodulatory agents in a tracheal allograft context.
- Predictive Value: Supports portfolio triage by quantifying luminal obliteration over time, allowing correlation of histopathological endpoints with mechanistic pathway modulation.
Screening & Assay Development
- Assay Readiness: Generates quantifiable histological outputs (e.g., luminal obliteration percentage via H&E staining) suitable for dose-response analysis in compound screening cascades.
- Reproducibility: Standardized suture techniques and postoperative monitoring enable inter-experimental consistency across laboratories, supporting assay transferability.
- Scalability: Murine model accommodates group sizes sufficient for statistical power in preclinical efficacy studies, facilitating downstream IND-enabling work.
Translational & Preclinical Research
- Disease Relevance: Both models develop obliterative lesions histologically similar to clinical OAD, enabling study of temporal progression and therapeutic intervention windows.
- Translational Continuity: Orthotopic model maintains physiological airflow and anatomic polarity, offering a clinically relevant platform to evaluate mucociliary clearance and airway biomechanics alongside fibrosis.
- Mechanistic De-risking: Heterotopic model isolates graft response from physiological airflow variables, enabling focused study of immunosuppression-dependent pathways in ectopic tissue.
- Risk-Adjusted Advancement: Differential OAD kinetics (28 days heterotopic vs 60 days orthotopic for maximal lesion) inform study design for acute versus chronic intervention strategies.
Pipeline & Workflow Integration
The tracheal transplantation models function as discovery-phase tools for target validation and mechanistic insight, with direct utility in lead optimization stages where airway-specific pathophysiology must be de-risked prior to pulmonary delivery or systemic candidate evaluation.
- Discovery Biology: Supports hypothesis testing of immune-fibrotic crosstalk via quantifiable histological endpoints, enabling pathway clarification in TGF-β, epithelial-mesenchymal transition, and macrophage polarization axes.
- Screening: Delivers standardized, quantitative readouts (luminal area reduction) that allow rank-ordering of compounds based on anti-obliterative efficacy in tracheal allografts.
- Analytics: Histomorphometric analysis provides objective, continuous data for statistical comparison between treatment groups, enabling robust effect size estimation.
- Translational Research: Orthotopic model’s preservation of tracheal continuity allows correlation of structural outcomes with functional respiratory parameters, bridging discovery to preclinical validation.
- Enterprise Reuse: Surgical models are adaptable across strain backgrounds and inducible genetic systems, supporting reuse in target validation, biomarker qualification, and combination therapy screening.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic ambiguity in OAD pathogenesis by enabling dissection of alloimmune versus non-immune drivers of fibrosis through model selection.
- Operational Value: Standardized microsurgical techniques and histological scoring minimize inter-laboratory variability, enhancing reproducibility in multi-site preclinical programs.
- Strategic Value: Informs go/no-go decisions by providing early efficacy signals in a human-relevant fibrosis model, reducing late-stage failure risk due to unanticipated airway toxicity.
- Portfolio Impact: Enables risk-adjusted prioritization of candidates based on disease modification potential in tracheal allografts, improving capital efficiency in fibrosis and transplant immunology portfolios.
Implementation Considerations
- Requires expertise in microsurgical techniques, including vessel handling, suture placement (8-0 and 6-0 prolene/Vicryl), and tracheal dissection under microscopy.
- Dependent on sterile surgical infrastructure, anesthesia protocols, and postoperative monitoring for graft survival and complication tracking.
- Necessitates histopathology training for consistent assessment of luminal obliteration using H&E staining and blinded scoring.
- Model choice must align with study hypothesis: orthotopic for physiologic airflow relevance, heterotopic for isolating graft-intrinsic responses.
- Limited by murine lifespan and graft survival timelines, requiring longitudinal planning for endpoint selection (e.g., 28 vs 60 days).
