BIOLOGICAL RESPONSE TO A SYNTHETIC CORNEA

We have designed a synthetic cornea that has a transparent hydrogel op tic and a porous skirt. The device has been implanted in rabbit cornea s. We have shown that keratocytes migrate into the device and deposit a complex extracellular matrix. The immediate response is detected in the surrounding stroma, and the secondary response is seen after cells have deposited a matrix in the disc. After implantation, a decrease i n keratan sulfate accompanied by an increase in dermatan sulfate was d etected in the surrounding tissue compared to the unwounded corneal st roma. The glycosaminoglycans in the disc resemble that of an injured s troma. The appearance of heparan sulfate and growth factors, bFGF and TGF beta, was not detected until 6 weeks after implantation. The growt h factors were detected at the interface between the device and the ti ssue and become more diffuse over time. Methods of controlled release in vivo were used to enhance the rate of fibroplasia and wound repair. While these were successful in the cornea itself, when combined with the synthetic cornea the response was magnified and the initial attemp ts yielded neovascularization and edema. Currently, efforts are being directed at controlling the release within the porous haptic so that f ibroplasia is enhanced while minimizing an inflammatory response. (C) 1998 Elsevier Science B.V.