Subendothelial deposition of von Willebrand's factor requires the presence of endothelial cells.

The presence of FVIII/VWF in human aortic subendothelium has been previously established. The present study was undertaken to determine the origin of this FVIII/VWF. Indirect immunofluorescence microscopy was employed to detect FVIII/VWF in rabbit aortas, after passage of a balloon catheter. Immediately after this de-endothelialization, FVIII/VWF was found to be present directly luminal to the internal elastic lamina. However, in the subsequent 5 days to 2 months, no FVIII/VWF was found on the luminal surface of exposed, nonre-endothelialized neointima. After endothelial cell regrowth, however, FVIII/VWF was again seen on the luminal surface. Thus these studies reveal that the deposition of subendothelial FVIII/VWF in neointima requires the presence of endothelial cells and that relatively trivial amounts of plasmatic FVIII/VWF are deposited on neointimal connective tissue after de-endothelialization.