- 期刊
- OpenAccess
Low-flow Conditioning of Decellularized and Re-seeded Homografts in a Novel Pulsatile Bioreactor
並列摘要
Cardiovascular tissue engineering has emerged as a promising approach to overcome limitations of conventional heart valve substitutes regarding lack of growth, repair, and remodeling capability by mimicking a native heart valve. The present study has demonstrated that long-term conditioning of decellularized and re-seeded aortic homografts in a low-flow pulsatile bioreactor results in an improved quality of tissue engineering constructs. Cryopreserved and thawed homografts were decellularized by a detergent mixture. Decellularized homografts were primarily seeded with fibroblasts (FB) followed by colonization with endothelial cells (EC), both isolated from human saphenous vein segments. Re-seeded homografts were exposed to low-flow conditions (750-1 100 mL/min) for a time period of 12 d. Topographical examination was performed by scanning electron microscopy (SEM). Cell layer thickness, composition of extracellular matrix (ECM) and inflammatory response was investigated by immunohistochemistry (IHC). SEM analysis of re-seeded homografts showed a confluent and intact cellular coverage before and after conditioning. IHC demonstrated a distinct thickening of cellular layer. Cell specific staining demonstrated a confluent EC lining with a multilayer of FB underneath. The expression of ECM components, cytoskeletal and gap junctional proteins increased by conditioning. Inflammatory proteins were expressed in a low level. The novel pulsatile bioreactor provides a strong tool for conditioning of re-seeded decellularized homografts. Moreover, conditioning results in an increased quality of ECM in regard to connectivity, stability and cell communication, creating native-like heart valve prostheses.