Factor VIII expression in the human embryonic eye. Differences between endothelial cells of different origin.

Corneal and vascular endothelial cells in sectioned human embryonic eyes were studied with respect to factor VIII expression. This was assessed by the use of two different antibodies which bind to factor VIII Rag with high specificity. It was found that whereas human vascular endothelium expressed factor VIII Rag as significant levels, corneal endothelium as well as all other ocular cells were found to be factor VIII-negative. This finding suggests that endothelial cells lining the inside of blood vessels are functionally different from those in the cornea.