Time-dependent expression of ICAM-1 & VCAM-1 on coronaries of the heterotopically transplanted mouse heart

To investigate the pathogenesis of accelerated graft atherosclerosis after cardiac transplantation, a genetically well-defined and reproducible animal model is required. We performed heterotopic intraabdominal heart transplantation between the two inbred strains of mice. Forty hearts from B10.A mice were transplanted into B10.BR mice. Recipients were sacrificed at 1, 3, 5, 7, 14, 28, and 42 days after implantation. The specimens from both donor and recipient were examined with fluorescent immunohistochemistry and the serial histopathologic changes were evaluated. In the donor hearts, ICAM-1 and VCAM-1 expressions were minimal at day 1 and they gradually increased, reaching their peaks on day 5 or 7 and remained unchanged by day 42. However, there were very little expressions in the recipients' hearts. Mean percent areas of intima in the donor coronaries revealed progressive increase by day 42. However, those in the recipients occupied consistently less than 5% of the lumen. In conclusion, we demonstrated that a heterotopic murine heart transplantation model was a useful tool to produce transplantation coronary artery disease and that adhesion molecules on the cardiac allografts were activated very early and remained elevated at all time-points, nonetheless the arterial lesion was detected after day 28 and its progression was accelerated thereafter.