Heterotopic rat heart transplantation (Lewis to F344): early ICAM-1 expression after 8 hours of cold ischemia.

Background: Primary graft dysfunction is a still poorly understood complication after cardiac transplantation. Ischemia/reperfusion injury contributes to different disorders resulting in impaired graft function.

Methods: In a heterotopic rat heart transplantation model we extended graft ischemic time up to 8 hours.

Results: Using immunohistochemistry we detected an up to 4-fold increase in intracellular adhesion molecule-1 (ICAM-1) expression during 4 hours of reperfusion, independent of ischemic time (30-minute ischemia: 7.65 +/- 2.15 without reperfusion, 19.46 +/- 4.6 after 4-hour reperfusion; 240-minute ischemia: 5.6 +/- 1.99 and 22.3 +/- 3.77; 480-minute ischemia: 3.7 +/- 1.56 and 13.1 +/- 2.2). Eight-hour ischemic allografts had an increase in CD8-positive cells (1.37 +/- 0.5 and 2.3 +/- 0.77) and a significant increase in MHC II expression (11.48 +/- 2.1 and 18.27 +/- 1.34) during 4 hours of reperfusion.

Conclusions: We hypothesize that these findings reflect an early inflammatory reaction in the allograft possibly triggered by oxidative stress. During therapeutic interventions, both of these pathways must be considered.