Jg. Maksoud et al., The effects of early and delayed immunosuppression in experimental tracheal transplantation with omentopexy, J PED SURG, 34(8), 1999, pp. 1223-1228
Background/Purpose: Best results in experimental tracheal allotransplantati
on are obtained when metachronous revascularization by omentopexy and immun
osuppression are used. Nevertheless, this method of revascularization impli
es in a 4-day period of ischemia to the graft. The aim of this study was to
assess the influence of the 4-day period of ischemia on host sensitization
as well as the effect of early or delayed immunosuppression on the outcome
of the grafts.
Methods: Thirty rabbits were submitted to tracheal allotransplantation and
divided according to position of the graft (orthotopic or heterotopic trans
plants) and the initiation of: immunosuppression (early or delayed). The qu
ality of the revascularization was evaluated by the identification of India
n ink, perfused through the abdominal aorta, inside the submucosal vessels.
The outcome of the grafts was evaluated by histological analysis according
to a semiquantitative scale of alterations.
Results: Grafts were better revascularized in heterotopic position. Grafts
with late immunosuppression presented good outcome only when heterotopicall
y positioned. No significant differences were observed in grafts placed het
erotopically or orthotopically when immunosuppression was initiated early a
fter the transplant.
Conclusions: Transient ischemia produced by metachronous revascularization
is not the single factor responsible for the histological alterations obser
ved in tracheal allografts. These alterations probably also are produced by
the activation of immune responses. This activation is more intense in mor
e ischemic grafts, but can be suppressed by early administration of immunos
uppression. Copyright (C) 1999 by W.B. Saunders Company.