[Construction of bioprosthetic heart valve with viable cells]

The ideal valve substitute should have cellular viability. Cryopreserved allograft has cellular viability in some degree, but the quantity, viability and function of the cells are affected by some preexistent factors such as chemical injury, hypoxia during valve processing and injury at the time of implantation. Early cellular autolysis and apoptosis take place not long after implantation, the implanted valve thus loses significant capacity to grow, remodel, or exhibit active metabolic functions. The viable donor cells are antigenic and capable of eliciting immune response, including antigenic and antigen-specific T cells. Calcification appears to originate in residual nonviable cells and their fragments. Proteinases released from endothelial and fibroblast cells of allograft heart valve will lead to the destruction of the valve matrix. One of the focuses of creating an ideal heart valve is the progressive recellularization of the valve matrix by the autologous cells. The acellular valve matrix, after being recellularized, has two characters: cellular viability and normal cellular function, which are the bases of creating ideal bioprosthetic valve with the potentiality of growing, repairing and remodeling.