Name: Video: Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice
Uploaded: 2023-11-10T12:40:00
Description: 176 Views. Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice

surgical procedure for intrapulmonary tracheal transplantation in mice

Exploring Obliterative Airway Disease in Lung Transplants

Lung transplantation has been established as an effective treatment for patients with end-stage respiratory diseases. However, the median survival rate for human lung transplant recipients is only approximately 6 years, with the development of obliterative bronchiolitis (OB), a type of obstructive airway disease (OAD), being a major cause of death after the first year post transplantation1.
Several animal models have been utilized to investigate the mechanism underlying OAD. One such model is the heterotopic tracheal transplantation (HTT) model2. In this model, tracheal grafts are implanted into the recipient&#39;s subcutaneous tissue or omentum. Ischemia-induced loss of tracheal graft epithelial cells occurs, followed by alloreactive lymphocyte infiltration and apoptosis of donor epithelial cells. Fibroblasts and myofibroblasts migrate around the trachea, producing an extracellular matrix. Finally, complete fibrous obliteration of the airway lumen occurs. The HTT model is technically simple, provides an in vivo environment, and offers high reproducibility.
Another model for studying OAD is the rat orthotopic tracheal transplantation (OTT) model, where tracheal grafts are interposed into the recipient&#39;s trachea to maintain physiological ventilation3. In this model, ischemia-induced depletion of donor epithelial cells results in their replacement by recipient epithelial cells within the trachea, forming an unobstructed airway accompanied by moderate fibrosis. Although these models have contributed to the understanding of airway obliteration after lung transplantation, they have limitations in terms of recapitulation of the lung parenchymal microenvironment.
Our research group introduced the rat intrapulmonary tracheal transplantation (IPTT) model, where tracheal grafts are implanted into the recipient lung4 (Figure 1). The IPTT model exhibits fibrous obliteration of the airway lumen occurring within the lung microenvironment. Furthermore, it has been successfully applied to mice that are technically more challenging than rat IPTT5,6,7,8,9,10. This adaptation of the murine IPTT model enabled us to delve deeper into the intricate details of the lung immunological environment of OAD after lung transplantation using transgenic mice.
The IPTT model possesses some unique features. One is neoangiogenesis, which is facilitated by pulmonary circulation and plays a crucial role in airway obliteration4,10. Additionally, the IPTT model exhibits lymphoid aggregates, some of which have high endothelial venules expressing peripheral node addressin, indicating that they are tertiary lymphoid organs (TLOs)7,8. TLOs resemble lymph nodes and consist of T cells, B cells, and frequently, a germinal center accompanied by follicular dendritic cells11,12. TLOs have been reported in various chronic inflammatory diseases, including airway obliteration, making the IPTT model suitable for investigating the role of TLOs in airway obliteration7,8,11,12,13. This paper presents the methodology of the murine IPTT model, with the goal of familiarizing researchers with this model and facilitate further investigations into airway obliteration following lung transplantation.

Author Spotlight: Investigating the Key Factors of Obliterative Bronchiolitis After Lung Transplantation

Murine Intrapulmonary Tracheal Transplantation: A Model for Investigating Obliterative Airway Disease After Lung Transplantation

Watch this Scientific Journal Video about Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice at JoVE.com

Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice

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176 Views. Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice

Video: Surgical Procedure for Intrapulmonary Tracheal Transplantation in Mice

Murine intrapulmonary tracheal transplantation (IPTT) is used as a model of obliterative airway disease (OAD) following lung transplantation. Initially reported by our team, this model has gained use in the study of OAD due to its high technical reproducibility and suitability for investigating immunological behaviors and therapeutic interventions.
In the IPTT model, a rodent tracheal graft is directly inserted into the recipient's lung through the pleura. This model is distinct from the heterotopic tracheal transplantation (HTT) model, wherein grafts are transplanted into subcutaneous or omental sites, and from the orthotopic tracheal transplantation (OTT) model in which the donor trachea replaces the recipient's trachea. 
Successful implementation of the IPTT model requires advanced anesthetic and surgical skills. Anesthetic skills include endotracheal intubation of the recipient, setting appropriate ventilatory parameters, and appropriately timed extubation after recovery from anesthesia. Surgical skills are essential for precise graft placement within the lung and for ensuring effective sealing of the visceral pleura to prevent air leakage and bleeding. In general, the learning process takes approximately 2 months.
In contrast to the HTT and OTT models, in the IPTT model, the allograft airway develops airway obliteration in the relevant lung microenvironment. This allows investigators to study lung-specific immunological and angiogenic processes involved in airway obliteration after lung transplantation. Furthermore, this model is also unique in that it exhibits tertiary lymphoid organs (TLOs), which are also seen in human lung allografts. TLOs are comprised of T and B cell populations and characterized by the presence of high endothelial venules that direct immune cell recruitment; therefore, they are likely to play a crucial role in graft acceptance and rejection. We conclude that the IPTT model is a useful tool for studying intrapulmonary immune and profibrotic pathways involved in the development of airway obliteration in the lung transplant allograft.

The murine intrapulmonary tracheal transplantation (IPTT) model is valuable for studying obliterative airway disease (OAD) after lung transplantation. It offers insights into lung-specific immunological and angiogenic behavior in airway obliteration after allotransplantation with high reproducibility. Here, we describe the IPTT procedure and its expected results.

Murine intrapulmonary tracheal transplantation (IPTT) is used as a model of obliterative airway disease (OAD) following lung transplantation. Initially ...