Obliterative airway disease in a porcine heterotopic bronchial allograft model

Representative animal models are needed for the study of posttransplant obl iterative bronchiolitis (OB). Because human OB originates in terminal bronc hi, the validity of tracheal models can be questioned. Using our heterotopi c model, we implanted pieces of a lobar bronchus subcutaneously into domest ic pigs. Five groups were included: autograft implants, allograft implants, allograft implants with 2 regimens of cyclosporine (CsA)azathioprine (AZA) -methylprednisolone (MP), and allograft implants with CsA-SDZ RAD-MP. Sampl es were harvested at 2 weeks and at 1, 2, and 3 months. The histological fi ndings were graded from 0 to 3. Following initial ischemic epithelial damag e, autograft implants recovered, but untreated allografts and those treated with CsA-AZA-MP were totally and permanently damaged within one month. In the group treated with CsA-SDZ RAD-MP, a maximal grade 1.5 +/- 0.5 epitheli al injury was seen at one month. Epithelial damage preceded and correlated with luminal obliteration. The obliterative lesions histologically resemble d human OB. Differences from our previous findings with terminal bronchiole s were minor. This study supports the use of larger-size airways in the stu dy of OB.