Non-volume-loaded heart provides a more relevant heterotopic transplantation model

Abstract Background We aimed to compare two techniques of heterotopic heart transplantation in rats. Non-volume-loaded (NL) and volume-loaded (VL) models were tested for their physiologic and immunologic properties to assess their suitability for transplant studies. Methods Syngeneic heterotopic heart transplants were performed according to the techniques previously described by Ono (NL) and Yokoyama (VL). Grafts were followed over 90 days with sequential echocardiography. Ex-vivo Langendorff perfusion was used to gain functional data. Allogeneic heart transplants were done to determine whether chronic allograft vasculopathy (CAV) develops at a different pace in both transplant models. Results The ischemic time during surgery was significantly longer using the VL model ( p p  = 0.004 on POD 90). Mean LV developed pressure and (d P  / d t )max were significantly higher with the NL model (61.1 ± 8.5 mmHg and 4261.7 ± 419.6 mmHg/s) than with VL hearts (19.9 ± 16.5 mmHg; p  = 0.011 and 924.8 ± 605.6 mmHg/s; p p p  = 0.807). Conclusions Since the coronary arteries in the VL model get perfused with partly deoxygenated blood, the myocardium suffers from chronic ischemic injury. We recommend using the NL model in preclinical transplant studies.