Models of Immunogenicity in Preclinical Assessment of Tissue Engineered Heart Valves

Tissue engineered heart valves offer an exciting alternative to traditional valve prostheses. Methods of construction vary, from decellularised animal tissue to synthetic hydrogels, but the goal is the same: the creation of a ‘living valve’ populated with autologous cells that may persist indefinitely upon implantation. Previous failed attempts in humans have highlighted the difficulty in predicting how a novel heart valve will perform in vivo. The final hurdle in bringing these prostheses to market is understanding the immune reaction in the short and long term. In particular, the chronic remodelling of a tissue engineered implant by macrophages remains poorly understood. No silver bullet exists, rather researchers must draw upon a number of in vitro and in vivo models to fully elucidate the effect a host will exert on the graft. This review details the methods by which the immunogenicity of tissue engineered heart valves may be investigated and reveals areas that would benefit from more research.