OBJECTIVE: To make a comparative evaluation of the behaviour of cryopreserved homografts and deccelularized porcine heterografts implanted in the right ventricular outflow tract of juvenile sheep as well as to report the initial clinical experience with deccelularized pulmonary homografts in patients submitted to the Ross procedure. METHOD: In group A, four cryopreserved homografts were implanted and group B consisted of four heterografts deccelularized with deoxicolic acid. In each group, two animals were sacrificed at 90 days and the other two at 150 days. The explants were evaluated macroscopically, and radiologically, besides histological examination with HE, Gomori and Sirius Red staining,. We also report our initial clinical experience with deccelularized pulmonary homografts in four patients submitted to the Ross procedure. RESULTS: A ll the animals survived. By echo all the implanted valves had normal function. Although the cusps had normal appearance in both groups, calcium content was higher in the cryopreserved valves and radiologically there were traces of calcification in the cryopreserved valves but none in the deccelularized valves. Cryopreserved homografts lost their cellularity while deccelularized heterografts were progressivelly repopulated by fibroblasts and were partially reendothelized. Four patients submitted to a Ross operation with deccelularized homografts had a good clinical outcome with normal function in their right sided homografts. CONCLUSIONS: Deccelularized heterografts were progressivelly repopulated by autologous cells and exhibted minimal tendency to calcification in this model. These results suggest that deccelularized heterografts may have some regenerative capacity and thus potencially greater durability than conventional cryopreserved homografts.
Homografts; Tissue Engineering; Heart valve
