Endothelial dysfunction and denudation in rat aortic allografts

Area of Science:

• Vascular Biology
• Transplantation Immunology
• Endothelial Cell Biology

Background:

• Endothelial cell (EC) dysfunction is a potential early predictor of graft vascular disease.
• Understanding early changes in graft endothelium is crucial for managing transplant outcomes.

Purpose of the Study:

• To investigate early functional and morphological changes in the graft endothelium within a rat aortic interposition allograft model.
• To correlate EC changes with leukocyte adhesion and vascular tone regulation post-transplantation.

Main Methods:

• Assessed EC function via acetylcholine-induced vasorelaxation in aortic rings at various post-transplant times.
• Evaluated EC morphology using silver staining and en face inspection.
• Monitored leukocyte adhesion and EC denudation in allografts versus syngeneic grafts.
• Investigated the effect of cyclosporine immunosuppression on EC changes.

Main Results:

• Reduced EC-dependent vasorelaxation was observed in allografts by post-transplant day 7 and 14.
• Massive leukocyte adhesion occurred at post-transplant day 7, followed by EC denudation at days 14 and 28 in allografts.
• Syngeneic grafts showed no significant EC dysfunction or morphological changes.
• Immunosuppression with cyclosporine prevented EC dysfunction and morphological alterations.
• EC dysfunction and leukocyte adhesion preceded other observed morphological changes.

Conclusions:

• Transplant-induced EC dysfunction in rat aortic allografts is detectable within one week post-transplantation.
• Early EC dysfunction is associated with increased leukocyte adhesion and appears to be immune-mediated.
• The rat aortic interposition allograft model effectively replicates early, immune-driven EC dysfunction seen in human patients.
• These findings highlight the critical role of early EC health in transplant success and suggest therapeutic targets.