Transplantation of the cryopreserved tracheal allograft in growing rabbits.
BACKGROUND
Surgical treatment of the congenital tracheal stenosis is challenging, and the long-term fate of transplanted tracheal allograft remains unclear. The authors evaluated the morphologic changes of the cryopreserved tracheal allograft after transplantation in a growing rabbit model.


METHODS
Each allograft (n = 7) was harvested from 90- to 120-day-old Japanese rabbits, immersed in the preservation solution, and stored in a programmable freezer until reaching -80 degrees c and then kept in liquid nitrogen for 1 week. Orthotopic tracheal transplantation of 7 tracheal rings in an end-to-end fashion was performed in age-matched young rabbits without immunosuppression. The grafts were assessed at 1 week, 1 month, and 3 months after transplantation. As controls, fresh autografts also were evaluated after the same procedure.


RESULTS
Two animals died of pneumonia. The body weight gain was similar in both groups. All grafts were patent, but no allografts showed normal growth in length or diameter. Microscopic findings of the allograft showed calcification of the tracheal cartilage without infiltration of inflammatory cells and marked lymphocyte proliferation in the subepithelium.


CONCLUSIONS
Cryopreserved tracheal allografts without immunosuppressant showed favorable patency of the trachea at 3 months; however, no growth of the allograft occurred in this animal model. The problem of calcification of the allograft remains to be solved.
Tanaka
Hiroshi
H
Division of Cardiovascular, Thoracic, and Pediatric Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Maeda
Kosaku
K
Okita
Yutaka
Y
D000818:Animals; D015925:Cryopreservation; D009926:Organ Preservation; D011817:Rabbits; D014132:Trachea / Q000601:surgery / Q000637:transplantation*; D014135:Tracheal Stenosis / Q000151:congenital* / Q000601:surgery*; D014184:Transplantation, Homologous