Tracheal replacement with cryopreserved tracheal allograft: experiment in dogs.
BACKGROUND
It has been difficult to perform tracheal allotransplantation without immunosuppression. To determine whether cryopreserved trachea can be used in tracheal replacement, we evaluated the viability of cryopreserved tracheal allografts in a canine model of immunosuppressant-free transplantation.


METHODS
Cryopreserved tracheal allografts, which had been frozen to -80 degrees C in a programmed freezer and then stored in liquid nitrogen (-196 degrees C) (group 1, n = 6), fresh tracheal autografts (group 2, n = 5), and fresh tracheal allografts (group 3, n = 4) were transplanted into the thoracic segment of the trachea using an omental flap without immunosuppressive agents.


RESULTS
All dogs in groups 1 and 2 survived, but in group 3, all 4 died of airway obstruction between 1 month and 2 months after operation. Histologically, the cryopreserved allografts displayed normal epithelium and cartilage, but the fresh allografts showed chronic inflammatory changes, no epithelium, and no cartilage.


CONCLUSIONS
Cryopreserved tracheal allografts maintain their structural integrity after transplantation. The cryopreservation process seems to reduce the allogenic response of the trachea in canine models. Therefore, we believe the cryopreserved tracheal allograft is an excellent choice for tracheal replacement.
Tojo
T
T
Department of Surgery III, Nara Medical University, Kashihara, Japan.
Niwaya
K
K
Sawabata
N
N
Kushibe
K
K
Nezu
K
K
Taniguchi
S
S
Kitamura
S
S
D000402:Airway Obstruction / Q000209:etiology; D000818:Animals; D002356:Cartilage / Q000473:pathology; D002908:Chronic Disease; D015925:Cryopreservation; D004195:Disease Models, Animal; D004285:Dogs; D004848:Epithelium / Q000473:pathology; D006085:Graft Survival; D007165:Immunosuppression Therapy; D009130:Muscle, Smooth / Q000473:pathology; D009852:Omentum / Q000637:transplantation; D009926:Organ Preservation; D011183:Postoperative Complications; D013524:Surgical Flaps; D015996:Survival Rate; D014132:Trachea / Q000473:pathology / Q000637:transplantation*; D014136:Tracheitis / Q000209:etiology; D014181:Transplantation Immunology; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous