Lining of viable and nonviable allogeneic and xenogeneic cardiovascular tissue with cultured adult human venous endothelium

With the aim of creating a confluent endothelial lining of cultured adult human saphenous vein endothelial cells on cardiovascular bioprosthetic tissues in vitro, we performed seeding on deendothelialized segments of viable or devitalized (in deionized water) human vein, porcine aorta, and bioprosthetic tissues preserved in glutaraldehyde. After being seeded, specimens were kept for 7 days under culture conditions. On glutaraldehyde-preserved tissue, seeding was performed after 3 weeks of elution of glutaraldehyde. Evaluation was performed with hematoxylin-eosin staining, immunohistochemical staining of von Willebrand’s factor and of collagen IV–related antigens, and scanning and transmission electron microscopy. The origin of the cells as derived from culture was verified by vital staining with a carbocyanine dye. Evaluation revealed a confluent lining of cultured human saphenous vein endothelial cells similar to native endothelium on both viable and nonviable human and porcine tissues. Collagen IV–related immunoreactivity was demonstrated close to the endothelial cells, corresponding to a de novo–formed basement membrane. Organelles and a basement membrane were demonstrated by transmission electron microscopy. The human saphenous vein endothelial cells seeded on glutaraldehyde-preserved tissues showed initial adherence but rounded up and detached on the second day of culture, probably because of residual glutaraldehyde. This study demonstrates that the native endothelium of allogeneic or xenogeneic viable and nonviable vascular tissue may be replaced by cultured endothelium in vitro. The structural similarities with a native endothelium suggest that in vitro endothelialization with cultured autologous endothelial cells may be used to improve performance of cardiovascular bioprostheses.