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 ad ult human saphenous vein endothelial cells on cardiovascular bioprosth etic tissues in vitro, we performed seeding on deendothelialized segme nts of viable or devitalized (in deionized water) human vein, porcine aorta, and bioprosthetic tissues preserved in glutaraldehyde. After be ing seeded, specimens were kept for 7 days under culture conditions. O n glutaraldehyde-preserved tissue, seeding was performed after 3 weeks of elution of glutaraldehyde. Evaluation was performed with hematoxyl in-eosin staining, immunohistochemical staining of von Willebrand's fa ctor and of collagen IV-related antigens, and scanning and transmissio n electron microscopy. The origin of the cells as derived from culture was verified by vital staining with a carbocyanine dye. Evaluation re vealed a confluent lining of cultured human saphenous vein endothelial cells similar to native endothelium on both viable and nonviable huma n and porcine tissues. Collagen IV-related immunoreactivity was demons trated close to the endothelial cells, corresponding to a de novo-form ed basement membrane. Organelles and a basement membrane were demonstr ated by transmission electron microscopy. The human saphenous vein end othelial cells seeded on glutaraldehyde-preserved tissues showed initi al 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 non viable vascular tissue may be replaced by cultured endothelium in vitr o. 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.