EXPERIMENTAL TRACHEAL ALLOGRAFT REVASCULARIZATION AND TRANSPLANTATION

The feasibility of tracheal allotransplantation with a fascial vascula r carrier was examined in three groups with varied dose sequences of i mmunosuppression. A control group (group 1) received no medication. Th e three experimental groups were given daily cyclosporine intramuscula r doses of 5 mg/kg (group 2), 5 mg/kg plus 3 mg/kg methylprednisolone (Solu-Medrol) (group 3), and 10 mg/kg (group 4) for 6 weeks or until d eath. Grafts were assessed by silicone dye infusion of the artery of t he fascial flap to examine their microcirculation and by quantitative histologic study, Group 1 evidenced complete rejection after a heterot opic revascularization period of 14 days. The allografts of the experi mental groups remained viable after 14 days of revascularization and c ould be transplanted orthotopically after this period. After transplan tation, the viability of group 2 tracheas was unpredictable with chang es ranging from mild to complete rejection. Group 3 evidenced well-pre served transplant viability with infection-induced necrosis at the ana stomoses caused by the corticosteroid component. All group 4 animals s urvived the follow-up period with normal allograft viability, Cyclospo rine in a dosage of 10 mg/kg per day can effectively suppress the immu ne response after transplantation of vascularized tracheal allografts. This experimental model will allow future studies to examine airway w all immunogenicity.