Adenosine injection prior to cardioplegia enhances preservation of senescent hearts in rat heterotopic heart transplantation

Advanced donor age is one of the risk factors for graft failure and is the leading cause of early death after heart transplantation. Better myocardial preservation methods should reduce graft failure. The purpose of this study was to determine if adenosine, which is known to enhance cardioplegic protection, enhances myocardial preservation during heart transplantation using older donors. We used a rat heterotopic heart transplantation model with Lewis rats that were at least 60 weeks old as donors. We injected saline (control) or adenosine (0.1 or 0.2 mg/kg) before cardioplegia, perfused with cold Celsior and stored the hearts in Celsior for 6 h at 4 degrees C. The grafts were transplanted into syngenic, 12-16-week old recipients, and blood and tissue were collected 3 h after reperfusion. Bolus injection of adenosine led to faster mechanical arrest after perfusion with Celsior and faster reanimation after reperfusion compared with controls. Adenosine treatment significantly reduced myocardial injury, as indicated by serum troponin I and creatine phosphokinase levels. The mRNAs for inflammatory cytokines were markedly increased in the control grafts, but were less upregulated in the grafts treated with adenosine. The grafts treated with adenosine also exhibited less mitochondrial damage, fewer infiltrating cells and a higher adenosine triphosphate content. Adenosine injection prior to perfusion of cardioplegia significantly reduced cold ischaemia/reperfusion injury in cardiac grafts from older donors and improved the stores of cellular energy after reperfusion. This procurement protocol may be clinically feasible and should be considered in the clinical setting, particularly for older donors.