Perfusion of rabbit hearts with pig blood results in complement mediated hyperacute xenograft rejection

Investigation of hyperacute rejection of discordant xenografts has been hampered by the lack of a model for the study of rapid time course events. In vivo models are unsuitable for observation of early rejection processes and, along with most ex-vivo perfusion preparations, are insensitive since no functional demand is placed on the organ which may have undergone extensive damage whilst still appearing viable. For this reason a blood perfused isolated working heart preparation has been developed. With left atrial and left ventricular loading the heart performs measurable work as it ejects into a mock circulation with both afterload and compliance components. When cardiac function is compromised the heart is no longer able to eject against the fixed afterload and both cardiac output and coronary circulation cease with resultant organ failure. The model is thus highly sensitive to minimal organ damage and has an easily identifiable endpoint. In the present study, we used this preparation to study the discordant species combination of rabbit hearts perfused with pig blood.