Angiogenic activity of the corneal epithelium.

A homogenate of corneal epithelial cells was tested to determine if it could induce vascularization in the cornea. Both fresh and cultured cells were used as sources of the homogenate which was evaluated in vivo using a self-contained system to perfuse it constantly into the corneal stroma. A vigorous growth of vessels resulted when the concentration of the homogenate exceeded a threshold of 20 micrograms per ml total protein. This capacity was not destroyed when the homogenate was heated. As a preliminary refinement of this response white blood cells were eliminated from the model with whole body X-irradiation. Vascularization occurred in leukopenic animals but was less than that observed in normal animals. It is concluded that the epithelial homogenate is able to provoke corneal vascularization in the absence of leukocytes.