Heart and spleen "twin grafts" in rats: morphology and function in permanent survivals

A new rat allograft model has been investigated for its potential to facilitate organ transplantation. In this procedure heart and spleen of male inbred LEW rat (RT1') were connected to the main abdominal vessels in inbred ACI rat (RT1a). With optimal surgical technique we obtain 64% permanent graft survival (5-14 months) in the splenectomized recipients. Cardiac histology ranged from preserved myocardium with moderate thickening of coronary artery walls to diffuse myocardial fibrosis with marked involutional changes of coronary arteries. Whereas palpation and EKG wrongly indicate good function beyond the fourth month, only the phonocardiogram shows the rapid functional loss which reflects the true morphologic involution.