Learning curve in tracheal allotransplantation

Area of Science:

• Regenerative Medicine
• Transplantation Immunology
• Surgical Innovation

Background:

• The first vascularized tracheal allotransplantation was performed in 2008, utilizing forearm implantation for revascularization.
• Subsequent cases addressed long-segment tracheal stenosis and chondrosarcoma, aiming to shorten the interval to orthotopic transplantation and safely withdraw immunosuppression.

Observation:

• All tracheal allografts achieved revascularization within two months following heterotopic forearm implantation.
• Immunosuppression withdrawal was initiated four months post-implantation, completed within six weeks in three patients.
• Mucosal lining repopulation by recipient cells was incomplete, leading to donor mucosa necrosis.

Findings:

• Partial loss of the tracheal allograft occurred in three patients due to incomplete recipient cell repopulation.
• One patient, who received additional measures for cell repopulation, experienced better outcomes.
• The trachea can function as a composite tissue allotransplant after heterotopic revascularization.

Implications:

• Maximizing recipient cell repopulation is critical for maintaining tracheal allograft viability after immunosuppression cessation.
• This study highlights the potential of tracheal allotransplantation but underscores the challenges of achieving complete mucosal integration.
• Further optimization of protocols is necessary to improve outcomes for composite tissue allotransplantation, particularly for airway reconstruction.